arema mre volume 1 print version v1arema manual for railway engineering 30-iii 1 3 4 introduction...

© 2015, American Railway Engineering and Maintenance-of-Way Association 30-i

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CHAPTER 30

TIES1

Chapter 30 is a combination of the former Chapter 3, “Ties & Wood Preservation,” and Chapter 10, “Concrete Ties.”

TABLE OF CONTENTS

Part/Section Description Page

1 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-31.2 Load Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-31.3 Vertical Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-51.4 Lateral Loads. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-81.5 Longitudinal Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-81.6 Rail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-91.7 Fastenings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-91.8 Influence of Cross Ties on Track Stiffness and Track Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-13

2 Evaluative Tests for Tie Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-12.1 Tie Performance Test Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-32.2 Bending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-32.3 Test 2: Rail/Plate Area Compression. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-82.4 Ability to Resist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-92.5 Tie Pad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-112.6 Fastener . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-142.7 Test 6: Tie and Fastener System Wear/Deterioration Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-192.8 Test 7: Fastener Electrical Impedance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-262.9 Test 8: Single Tie Lateral Push . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-26

3 Solid Sawn Timber Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-13.1 Timber Cross Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-33.2 Timber Switch Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-123.3 Tie Tests and the Economics of Service Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-15

1 The material in this and other chapters in the AREMA Manual for Railway Engineering is published as recommended practice to railroads and others concerned with the engineering, design and construction of railroad fixed properties (except signals and communications), and allied services and facilities. For the purpose of this Manual, RECOMMENDED PRACTICE is defined as material, device, design, plan, specification, principle or practicerecommended to the railways for use as required, either exactly as presented or with such modifications as may be necessary or desirable to meet the needs of individual railways, but in either event, with a view to promoting efficiency and economy in the location, construction, operation or maintenance of railways. It is not intended to imply that other practices may not be equally acceptable.

© 2015, American Railway Engineering and Maintenance-of-Way Association

30-ii AREMA Manual for Railway Engineering

TABLE OF CONTENTS (CONT)

Part/Section Description Page

3.4 Substitute Timber Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-183.5 The Handling of Ties from the Tree into the Track . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-203.6 Wood Preserving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-293.7 Specifications for Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-363.8 Recommended Practice for the Manufacture of Two-Piece Steel Doweled Laminated Cross Ties (TPSDLC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-423.9 Specifications for Timber Industrial Grade Cross Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-46

4 Concrete Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-14.1 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-44.2 Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-114.3 Tie Dimensions, Configuration and Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-164.4 Flexural Strength of Prestressed Monoblock Ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-194.5 Flexural Strength of Two-Block Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-234.6 Longitudinal Rail Restraint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-244.7 Lateral Rail Restraint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-244.8 Electrical Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-274.9 Testing of Monoblock Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-274.10 Testing of Two-Block Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-354.11 Recommended Practices For Shipping, Handling, Application and Use . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-404.12 Ballast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-424.13 Ties for Turnouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-424.14 Ties for Grade Crossing Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-474.15 Cast-In and Post-Installed Inserts for Concrete Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-484.16 Concrete Tie Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-49

Commentary (2015). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-50

5 Engineered Composite Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-15.1 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-25.2 Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-35.3 Physical and Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-45.4 Special Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-75.5 Quality Control, Inspection, and Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-115.6 Engineered Composite Ties for Open Deck Bridges. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-12

6 Steel Ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-16.1 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-16.2 Physical & Mechanical Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-16.3 Steel Switch Ties, Steel Grade Crossing Ties & Other Specialty Steel Ties . . . . . . . . . . . . . . . . . . . . . . . 30-6-26.4 Ballast & Sub-Grade Requirement for Steel Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-26.5 Tamping & Compaction of Ballast in Steel Tie Track & Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-36.6 Steel Tie Identification, Marking of Tie, Inspection and Quality Control. . . . . . . . . . . . . . . . . . . . . . . . . 30-6-3

Chapter 30 Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-G-1

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30--1

Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-1

30-R-1


AREMA Manual for Railway Engineering 30-iii

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INTRODUCTION

The Chapters of the AREMA Manual are divided into numbered Parts, each comprised of related documents (specifications, recommended practices, plans, etc.). Individual Parts are divided into Sections by centered headings set in capital letters andidentified by a Section number. These Sections are subdivided into Articles designated by numbered side headings.

Page Numbers – In the page numbering of the Manual (30-2-1, for example) the first numeral designates the Chapter number, the second denotes the Part number in the Chapter, and the third numeral designates the page number in the Part. Thus, 30-2-1 means Chapter 30, Part 2, page 1.

In the Glossary and References, the Part number is replaced by either a “G” for Glossary or “R” for References.

Document Dates – The bold type date (Document Date) at the beginning of each document (Part) applies to the document as a whole and designates the year in which revisions were last made somewhere in the document, unless an attached footnote indicates that the document was adopted, reapproved, or rewritten in that year.

Article Dates – Each Article shows the date (in parenthesis) of the last time that Article was modified.

Revision Marks – All current year revisions (changes and additions) which have been incorporated into the document are identified by a vertical line along the outside margin of the page, directly beside the modified information.

Proceedings Footnote – The Proceedings footnote on the first page of each document gives references to all Association action with respect to the document.

Annual Updates – New manuals, as well as revision sets, will be printed and issued yearly.


30-iv AREMA Manual for Railway Engineering

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© 2015, American Railway Engineering and Maintenance-of-Way Association 30-1-1

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30Part 1

General Considerations

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FOREWORD

This recommended practice is intended to provide necessary guidance in the design, manufacture, and use of cross ties and their components for standard gage ballasted main line freight and passenger railway track systems. The recommended practice contains minimum performance requirements of components for railway track based on a variety of permissible tie spacings and ballast depths. Track constructed of tie and fastener components meeting the recommended practices applicable to the anticipated usage should be expected to give satisfactory performance under current AAR-approved maximum axle loads. These recommended practices are applicable for conditions using 1997 AAR interchange requirements, and with axle loads up to 39 tons.

The recommended practice covers materials, dimensions, and structural strength of cross ties. In addition, longitudinal and lateral load restraint requirements as well as the electrical performance requirements of rail fastener and tie combinations aregiven. Laboratory tests for the determination of the suitability of new designs are specified. The recommended practice does not cover techniques or equipment for the manufacture of cross ties or fastenings.

Where current specifications are recommended by organizations such as the American Society for Testing and Materials, the American Concrete Institute, American Wood Preservers Association, or other technical societies, they are made part of this recommended practice by reference.

Ties


30-1-2 AREMA Manual for Railway Engineering

TABLE OF CONTENTS

Section/Article Description Page

1.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-3

1.2 Load Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-3

1.3 Vertical Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-51.3.1 Tie Spacing (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-51.3.2 Cross Tie Dimensions (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-51.3.3 Load Distribution (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-61.3.4 Impact Factors (2002). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-61.3.5 Ballast and Subgrade (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-61.3.6 Ballast and Ballast Pressure (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-7

1.4 Lateral Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-81.4.1 Lateral Load Environment (2015) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-81.4.2 Lateral Load Distribution (2015) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-8

1.5 Longitudinal Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-81.5.1 Load Environment (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-81.5.2 Longitudinal Load Distribution (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-9

1.6 Rail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-91.6.1 Flexure Requirement (2002). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-91.6.2 Rail Joints (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-9

1.7 Fastenings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-91.7.1 Introduction (2009). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-91.7.2 General (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-101.7.3 Fastener Requirements – General (2012) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-101.7.4 Fastener Requirements (2009) R(2012) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-13

1.8 Influence of Cross Ties on Track Stiffness and Track Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-131.8.1 Definition of Vertical Track Stiffness (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-131.8.2 Track Transition Problem (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-141.8.3 Track Transition Remedies and Practices (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-14

LIST OF FIGURES

Figure Description Page

30-1-1 Estimated Distribution of Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-730-1-2 Schematic of Various Pads and Ballast Mat in a Track Structure (See Reference 7) . . . . . . . . . . . . . . . . . 30-1-15

LIST OF TABLES

Table Description Page

30-1-1 Distribution of nominal vertical wheel loads (measured at wheel rail interface) . . . . . . . . . . . . . . . . . . . . 30-1-430-1-2 Distribution of peak vertical wheel loads (measured at wheel rail interface) . . . . . . . . . . . . . . . . . . . . . . . 30-1-4



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LIST OF TABLES (CONT)


30-1-3 Wheel to Rail Loads (kips) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-530-1-4 Typical Fastening System Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1-10

SECTION 1.1 INTRODUCTION

In supporting and guiding railway vehicles, the track structure must restrain repeated lateral, vertical, and longitudinal forces.As elements of the track structure, individual cross ties receive loads from the rails or fastenings and in turn, transmit loads to the ballast and subgrade. Consequently, the design of a tie affects and is affected by characteristics of other components of thetrack structure. The design of cross tie track systems and components must consider:

• The rail, fastenings, tie, ballast, sub-ballast, and subgrade;

• The quality of each component, method of manufacture, installation, and maintenance;

• Durability and material specific degradation mode evaluation;

• The direction, magnitude, and frequency of traffic-imposed loads;

• The effect of climate and environmental factors such as temperature, sunlight and weather;

• The overall economics of installation and maintenance; and

• The need to support and guide railway vehicles while restraining repeated lateral, vertical, and longitudinal forces.

The recommended practices, which follow, provide the basic guidance for the selection, design, and application of cross ties systems of various materials. Success in their application will require careful supervision on the part of the engineer to ensurethat all components meet required standards and that the system is properly installed and maintained.

SECTION 1.2 LOAD ENVIRONMENT

Table 30-1-1 and Table 30-1-2 define the load environment that is expected to be encountered on North American Freight and Passenger Railroads. Table 30-1-1 describes the nominal vertical wheel loads for a variety of freight and passenger traffic types, while Table 30-1-2 describes the peak vertical wheel loads. This data was obtained from wheel impact load detector (WILD) sites which measure wheel loads at the wheel-rail interface. WILD sites are located on tangent track with concrete crosstie infrastructure. The data provided are only vertical loads, as the lateral loads in WILD site locations are generally negligible, due to their location on tangent track. The nominal wheel load table is used as an estimation of the static load distribution. The WILD site where these data were collected uses an algorithm to filter out dynamic impacts and generates nominal wheel loads that are generally within one percent of the static load. For practical purposes, these nominal loads can beused as an approximation of static loading conditions. Speed is not included because it does not impact nominal wheel load and only results in a small increase of peak wheel load. Additionally, the data collected from WILD sites contains a large variety of speeds, ranging from approximately 10-70 mph for freight trains and 10 to 150 mph for passenger trains.1 Table 30-1-3 presents the available data in terms of horizontal and longitudinal loads that can be expected at the wheel/rail interface. The service categories are distinguished as follows. Mainline Freight represents lines other than Light Density Freight. Light

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Density Freight represents lines with less than five million gross tons and excludes A/C Traction. High Speed Passenger represents passenger loadings whether in mixed service or on dedicated routes. Speeds are given in miles per hour.4

1Source of data: Van Dyk, Brandon. 2013. Characterization of the loading environment for shared-use railway superstructure in North America. MS Thesis, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Graduate College, Urbana, Illinois.2Source of data: Union Pacific Railroad; Gothenburg, Nebraska; January 2010 – (838,352 wheels)3Source of data: Amtrak; Edgewood, Maryland, Hook, Pennsylvania, and Mansfield, Massachusetts; November 2010 – (522,949 wheels)4These values are intended to represent the North American loading regime and are not intended to be used for design. The design procedure is presented elsewhere in this chapter.

Table 30-1-1. Distribution of nominal vertical wheel loads (measured at wheel rail interface)

Car Type

Nominal Wheel Load (kips)

Mean 95% 97.5% 99.5% 100%

Unloaded Freight Car2 7 10 11 14 15Loaded Freight Car2 34 40 41 42 46Intermodal Freight Car2 21 36 37 40 51Freight Locomotive2 34 37 38 39 44Passenger Locomotive3 27 36 38 40 43Passenger Coach3 15 19 19 21 46Transit No Data Available

Table 30-1-2. Distribution of peak vertical wheel loads (measured at wheel rail interface)

Car Type

Peak Wheel Load (kips)

Mean 95% 97.5% 99.5% 100%

Unloaded Freight Car2 11 21 27 40 101Loaded Freight Car2 43 57 66 85 157Intermodal Freight Car2 28 47 55 75 142Freight Locomotive2 43 54 58 69 110Passenger Locomotive3 39 50 54 64 94Passenger Coach3 24 36 43 59 109Transit No Data Available




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* This data estimated or interpolated** Generally accepted superelevation practice excludes these values

SECTION 1.3 VERTICAL LOADS

1.3.1 TIE SPACING (2002)

Tie spacing affects rail flexural stress, compressive stress on ballast and roadbed, lateral resistance of the track structure andthe flexural stress in the ties themselves. For a given set of tie dimensions and wheel loads, the consequences of increasing tiespacing are higher rail bending moments and corresponding deflections and stresses within the individual ties. For the case ofconstant tie, ballast, and subgrade characteristics, wider tie spacings bring about larger track depression per unit of wheel load;i.e., lower track modulus. Changes in tie spacing also will have a significant influence on unit stress and track modulus as wellas a corresponding impact on track surfacing cycles.

These recommended practices cover cross ties intended for track designs using center-to-center spacings of cross ties of between 18 inches and 30 inches. These recommended practices do not exclude alternate spacings and configurations. However, center-to-center spacings outside of these limits will require additional analysis.

1.3.2 CROSS TIE DIMENSIONS (2002)

Use of longer, wider or stiffer ties, which increase the tie-to-ballast bearing area, has many of the same effects as reducing tiespacing. There are, however, limits beyond which an increase in tie size is ineffective in reducing track stress or increasingtrack modulus. The concentration of tie-to-ballast load can decrease with lateral distance from the rail. The rate of decrease of load with distance is higher for flexible tie materials and designs. There is, therefore, a point beyond which increasing the

Table 30-1-3. Wheel to Rail Loads (kips)

CURVE <2 DEG 2-5 DEG >5 DEGSPEED LAT LONG LAT LONG LAT LONG

MAINLINE FREIGHT<40 20* 50 30* 50 30 50

40 to 60 30* 50 30* 50 30 50>60 30 50 30 50 ** **

LIGHT DENSITY FREIGHT (no A/C Traction)<40 20* 30 30* 30 30 30

40 to 60 30 30 30 30 30 30>60 30 30 30 30 ** **

HIGH SPEED PASSENGER<90 10 25 18 25 20* 25>90 18 25 18 25 ** **

TRANSITNo data available

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length of the tie will fail to significantly reduce unit bearing load. There are, in addition, required right-of-way clearances and machinery limitations which restrict tie length.

Widening the tie design has similar effects as increasing tie length. Widening tie design, however, beyond the point where it ispractical to compact ballast beneath the tie is ineffective.

These recommended practices cover tie designs between 7 ft. 5 inches and 9 ft. 0 inches in length and between 8 inches and 13 inches in width at their bottom surface. Ties with dimensions outside of these limits will require additional analysis.

1.3.3 LOAD DISTRIBUTION (2002)

The foregoing discussion and the requirements following are based on the knowledge that wheel loads applied to the rail will be distributed by the rail to several ties. This distribution of loads has been confirmed in field investigations. The distributionof load is dependent upon the tie properties, spacing, ballast and subgrade reaction, rail fastening system and rail stiffness. The percentage of wheel-to-rail load carried by an individual tie varies from location to location. Figure 30-1-1 summarizes the results of beam on elastic foundation calculations for the given values of in lb/in/in into an estimate of the load distribution. While rail stiffness does influence these percentages, its effect is small compared to other factors such as tie spacing. The values chosen are intended to offset variations resulting from other influences.

1.3.4 IMPACT FACTORS (2002)

The requirements of these recommended practices are based on calculations including an assumed impact factor. This factor is a percentage increase over static vertical loads intended to estimate the dynamic effect of wheel and rail irregularities.

1.3.5 BALLAST AND SUBGRADE (2002)

In addition to tie size and spacing, ballast depth and subgrade modulus are also significant in the manner a particular track design distributes vertical loading. Increasing ballast depth tends to spread individual tie loads over a wider area of subgrade,thereby reducing the unit subgrade load and consequent track depression. Thus, the effect of increased ballast depth can be more significant, within limits, than that of reduced tie spacing. Refer to Chapter 1, Roadway and Ballast.




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1.3.6 BALLAST AND BALLAST PRESSURE (2002)

The engineer must ensure that the design of track does not result in over-stress of ballast or subgrade. To do so, considerationmust be given to wheel loads, distribution factor, impact factor, unit bearing capacities of the ballast and subgrade, and crosstie dimensions and spacing.

1.3.6.1 Ballast Pressure

While tie-to-ballast pressure is not uniformly distributed across or along the bottom of a cross tie, however an approximate calculation can be made of average pressure at the bottom of the tie. The average pressure at the tie bottom is equal to axle load, modified by distribution and impact factors, and divided by the bearing area of the tie.

It should be noted here that there are differing methods of determining the bearing area of the tie for use in ballast pressurecalculations. In Chapter 16, Part 10, Article 10.11.1, Paragraph b(7) the bearing area of the tie is 2/3 of the footprint of the tie.

Figure 30-1-1. Estimated Distribution of Loads

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In Chapter 30, Part 4, Article 4.1.2.5.1.1, Paragraph a the effective bearing area of the tie is the entire footprint of the tie. Likewise there are differing standards for the recommended maximum allowable ballast pressure. Chapter 16, Part 10,Article 10.2.2.3 limits the ballast pressure to 65 psi while Chapter 30, Part 4, Article 4.1.2.5.1.1, Paragraph b limits the ballast pressure to 85 psi. Accordingly, the tie designer is cautioned to consider the context of these standards before applying them.

1.3.6.2 Subgrade Pressure

The pressure exerted by ballast on the subgrade depends upon the tie-to-ballast pressure, the load distribution pattern throughthe ballast, and the depth of ballast. Refer to Chapter 1, Part 2.

SECTION 1.4 LATERAL LOADS

1.4.1 LATERAL LOAD ENVIRONMENT (2015)

The lateral loads generated by moving railway equipment are applied by wheel treads and flanges to the rails, which in turn must be held in place by fastenings, ties, and ballast.

Lateral stiffness of rail distributes lateral loads to fasteners and their ties. Structural strength of fastenings and ties hold the rail to gage. The mass of ties, friction between the ties and ballast, lateral bearing areas of ties (end surface), and the mass of ballast all act to restrain lateral tie movement.

Lateral track stability can, therefore, be increased by decreasing the spacing of ties of similar dimensions, increasing tie mass,increasing end bearing area of ties per unit length of track, and by increasing frictional resistance between ties and ballast.Structural strength of fastenings must be commensurate with the lateral load individual ties restrain, which in turn is determined by lateral rail stiffness, tie spacing, frictional characteristics of the fastening system, and lateral fastening systemstiffness.

The magnitude of lateral loads which must be restrained depends not only upon the dimensions, configuration, weight, speed, and tracking characteristics of the equipment, but also upon the geometric characteristics of the track structure. Both the routegeometry - whether the track is straight, curved, or how sharply curved -- and the local track geometry -- the irregularities andsmall deviations from design -- influence the magnitude of lateral load.

1.4.2 LATERAL LOAD DISTRIBUTION (2015)

C - Section 4.7 Lateral Rail Restraint, C-Lateral Force Distribution, Paragraph a implies the lateral load distribution mimics the vertical load distribution given in Figure 30-4-1. This assumption may be too generalized since field observations suggest that lateral loads are distributed to less ties than vertical loads. Accordingly, the designer is cautioned that field conditions such as curvature, grade, speed, and traffic type must be considered in the tie and fastener design.

SECTION 1.5 LONGITUDINAL LOAD

1.5.1 LOAD ENVIRONMENT (2002)

The longitudinal load developed by the combination of thermal stress in continuous welded rail and by traffic is transferred bythe fastenings to the ties and ultimately restrained by mass internal friction of ballast. Consequently, the longitudinal bearingarea (side area) of ties per unit of track length, friction between bottom of ties and ballast, and physical properties of ballast




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ultimately determine the track resistance to longitudinal movement. Resistance to rail movement with respect to ties is determined by the characteristics of fasteners. While total restraint of longitudinal rail movement is generally desirable, thereare situations where such restraint is impractical or undesirable.

1.5.2 LONGITUDINAL LOAD DISTRIBUTION (2002)

Rail must be restrained to avoid excessive longitudinal movement. Longitudinal movement of the rail can be induced by temperature change and/or traffic. In practice, fasteners on ties with 24 inch spacing providing 2.4 kips per tie per rail forlongitudinal movement due to temperature and traffic induced loads have proved satisfactory. However, experience has shown that while this value is sufficient for general service, there are specific locations of excessive longitudinal force where thisvalue understates actual field conditions.

SECTION 1.6 RAIL

1.6.1 FLEXURE REQUIREMENT (2002)

The interaction of rail and ties has been discussed in Section 1.3 and 1.4 with respect to distribution factors, tie spacing, and vertical loads. The flexure stress generated in rail under load is a function of applied bending moment and the section modulusof rail. Rail bending moment is in turn determined by wheel load, axle spacing, and track modulus. While conventional tie spacing is in the range of 19 inches to 24 inches, most heavy modern rail sections are capable of bearing current wheel loads on tie spacings of up to 30 inches with normal ballast support without distress. However, the designer is cautioned that increasing the tie spacing can reduce the fatigue life of the rail even though the stress levels are within allowable limits. Forrail sections lighter than 115 lb/yd, it is recommended that the designer calculate the maximum rail bending stress.

1.6.2 RAIL JOINTS (2002)

a. To achieve the maximum benefits and economy from any tie, it is recommended that, in main-line track, they be used in conjunction with continuous welded rail. When ties are used in conventional bolted track or at the ends of continuous welded rail, care should be exercised to ensure that the juncture of two rails can be properly supported and fastened. The magnitude of impacts on a tie placed under the juncture of two rails could be destructive to the rail seat and fastenings.

b. Special considerations may be required when ties are installed within the limits of insulated joints or special trackwork such as turnouts and crossovers.

SECTION 1.7 FASTENINGS

1.7.1 INTRODUCTION (2009)

This section provides information relating to rail fasteners for railway ties of all types. “Fasteners or Elastic Fasteners” isdefined here as a system of components that function together to fasten rail to tie. The fastening system works together with the tie to maintain rail gauge under load.

For general information on spikes, tie plates, and rail anchors and other non-elastic fastener parts, refer to Chapter 5, Track.

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1.7.2 GENERAL (2006)

The required function(s) of a fastening system may vary greatly with the type of tie and fastening system used. The function(s) of a fastening system include providing and maintaining various degrees of the following: gauge restraint, transferof vertical, lateral and longitudinal loads from rail to tie, load / impact attenuation, electrical isolation and rail seat cant.

This section is not intended to preclude new technologies but rather reflects current industry practices.

1.7.2.1 Typical fastening system functions are as shown in Table 30-1-4 for various types.

Table 30-1-4. Typical Fastening System Functions

1.7.3 FASTENER REQUIREMENTS – GENERAL (2012)

The fastening system shall be of adequate design and manufacture to provide the following functions under all expected loading and environmental conditions:

Provide adequate lateral strength to maintain rail gage.

Constrain the rail against rollover.

Control longitudinal rail movement due to thermal and tractive forces, and minimize rail gap in the event of a rail break.

All fastening components, including hardware cast into the tie, shall be suitably resistant to corrosion and able to withstand repeated loads within the railway track environment without fatigue failure or excessive maintenance requirements. Use of metals of widely divergent electrical potential in contact or close proximity to one another is not recommended.

Rail fastening systems typically contain components that perform functions as follows.

1.7.3.1 Spring Clip

a. Spring Clips shall be of suitable design and material to conform to Article 1.7.3.

b. Where deemed necessary, spring clips shall be provided with a coating to protect against corrosion and stress corrosion cracking.

c. Spring clips shall be designed to prevent failure by fatigue within the expected dynamic deflection range.

Function

Tie Type

GaugeRestraint

LoadTransfer

Provide Cant

ImpactAttenuation

BearingForce Dist.

ElectricalIsolation

Wood Y Y Y N Y NConcrete Y Y N Y N Y

Composite Y Y Y N Y NSteel Y Y N N N Y/N




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1.7.3.2 Insulator

Insulation shall be used where necessary to prevent interference with signal systems and deterioration of the fastening system through electrical leakage. Insulation may be provided by insulators placed at appropriate locations in the fastening assembly or by other acceptable means.

Insulators shall be of dimensions and materials suitable for use with the fastener components. Insulator material shall providethe required chemical and physical properties to resist effects of environment exposure and traffic loads, and to satisfy the requirements of the tests specified in Section 4.9, Testing of Monoblock Ties.

a. Insulators shall be of suitable design and material to conform to Article 1.7.3. Insulators are typically expected to provide electrical isolation as noted in Table 30-1-4.

b. Insulators, when required, shall provide for suitable protection of the gauge restraining shoulder face from abrasive wear resulting from lateral loading of the ties by rail traffic.

c. The following insulator material property tests are recommended for evaluating plastic materials intended for insulator manufacture:

(1) Electric Resistivity, ASTM D257.

(2) Notched Izod Impact, ASTM D256.

(3) Flexural Modulus and Strength, ASTM D790.

(4) Water Absorption, ASTM D570.

(5) Tensile and Elongation, ASTM D638.

(6) Compressive Strength, ASTM D695.

(7) Heat Deflection Temp. (ASTM D648)

(8) Resistance to ozone (ASTM 518)

(9) Resistance to fluids such as water, acids, alkali, petroleum oils, and synthetic lubricants (ASTM D471)

For plastic mateirals belonging to the polyamide (Nylon) family these tests are recommended to be executed on specimens dry as molded and conditioned (ASTM D618).

1.7.3.3 Shoulders/Inserts

Shoulders and inserts provide anchorage points within ties for rail fastening systems and other miscellaneous components.

a. Shoulders/inserts shall be of suitable design and material to conform to Article 1.7.3.

b. Shoulders provide for the transfer of lateral loads from the railseat assembly to the tie.

c. Inserts shall conform to Chapter 30, Article 4.9.1.9.

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1.7.3.4 Railseat Pads

Railseat Pads shall be used between the rail and concrete ties to to reduce impact and vibration effects on the track structureand minimize railseat deterioration. Railseat Pads are typically expected to provide electrical isolation as noted in Table 30-1-4.

For curves over 3 degrees and for other severe service areas, special consideration must be given to pad selection. Three-partsandwich pads consisting of lower layer foam gasket, intermediate layer abrasion plate, and top layer of shape factored thermoplastic material have been effective for these areas. Two part sandwich pads consisting of lower layer abrasion element and top layer shape factored thermoplastic material, as well as one-piece pads, can also be effective.

a. Railseat pads shall be of suitable design and material to conform to Article 1.7.3 and satisfy requirements of the test specified in Section 4.9. Railseat pads shall be made of a material suitable for long term service in the expected track environment.

b. Tie pad shall have minimum width equal to the base width of the Rail (+1/8–0 inches) (3 mm). It shall be shaped or have indicators that will provide correct orientation during installation. The thickness of the pad shall not be less than 5 mm.

c. Railseat pads, when required, shall provide suitable protection of the tie railseat from abrasive wear and wheel impact loads.

d. All pads shall be marked in a permanent manner to indicate manufacturer and pad identification.

e. The following railseat pad property tests are recommended for evaluating suitable railseat pad materials or for comparing relative values between dissimilar materials:

(1) Hardness, ASTM D2240, to appropriate scale.

(2) Compression Set, ASTM D395:

(a) Room Temp, 23 degrees C;

(b) High Temp, 70 degrees C;

(c) Low Temp, -20 degrees C (ASTM D1229), as applicable.

(3) Elongation/Tensile Strength, before and after aging, ASTM D412 and ASTM D573.

(4) Ozone Resistance, ASTM D518

(5) Abrasion Resistance, ASTM D2228

(6) Volume Resistivity, ASTM D257

(7) Resistance to fluids such as water, acids, alkali, petroleum oils, and synthetic lubricants (ASTM D471).

(8) Vicat softening temperature (ASTM D1525).

f. For initial design qualification testing, three railseat pads shall be selected at random from a lot not less than 10 pads atrandom for laboratory testing. Railseat pads tests shall be conducted using a tie block, as described in Article 4.9.1.15,following the Sequence of Design Tests specified in Article 4.9.1.3.

Due to the wide variations in service conditions, environment specific test requirements are left to the end user’s discretion.




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1.7.3.5 Spikes, Rail Anchors: Refer to Chapter 5, Track

1.7.3.6 Tie Plates: Refer to Chapter 5, Track

1.7.3.7 Cap Screws and Rail Clips

Cap screws used with rail clips shall be a minimum of 3/4 inch (19 mm) in diameter and of sufficient length to provide a minimum engagement of 1 inch (25 mm) but not exceed 1-1/2 inches (38 mm). They shall have a minimum proof load of 28.4 kips (126.32 kN).

1.7.4 FASTENER REQUIREMENTS (2009) R(2012)

1.7.4.1 Wood and Composite Ties

a. Tie plates support the rail, establish railseat cant, and distribute loads to the tie surface. Tie plates typically feature integral shoulders.

b. Spring clips are used to secure the rail to the tie plate, and as appropriate, tie plate to the tie. Follow manufacturer’s recommendations for any special fastener specific considerations (e.g., size and depth of pre-drill holes).

For general information on spikes, tie plates, rail anchors for longitudinal restraint and other non-elastic fastener parts, refer to Chapter 5, Track.

1.7.4.2 Concrete Ties

a. Ductile iron shoulders and inserts typically are cast into the concrete ties.

b. Electrical insulation is required for use on signaled track.

c. Tie railseat pad usage is as required to suit application. The selection of railseat pad type shall be dictated by user requirements.

d. Insulators are typically used for setting and maintaining gage on concrete tie tracks.

1.7.4.3 Steel Ties

a. Railseat pads and insulators are required when using steel ties on signaled track.

b. Shoulders for steel ties can be welded on, of the hook-in variety, riveted in place or formed to create a rail seat.

SECTION 1.8 INFLUENCE OF CROSS TIES ON TRACK STIFFNESS AND TRACK TRANSITIONS1

1.8.1 DEFINITION OF VERTICAL TRACK STIFFNESS (2006)

Vertical track stiffness or vertical track modulus, k, represents the vertical response of the entire track system below the base of the rail including cross ties, fasteners, tie pads, ballast, and subgrade. Each of these components contributes to the overalltrack modulus, and it is important to utilize appropriate track components to maintain uniform stiffness while traversing all

1 See References.

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subgrades and structures. Failure to do so can cause variations in track stiffness, which may result in increased dynamic wheelloading, accelerated track degradation (rail batter, surface degradation etc.), and poor ride quality.

Cross ties significantly influence the vertical response of the track through their bending stiffness, vertical compressibility in the rail-seat region, tie spacing, tie length, tie bearing area, and rigidity (toe load) of the employed fastening system. Typicaltrack modulus values for some tie configurations in main-line track are given below:

Wood-tie track, after tamping k = 1,000 lb/in2

Wood-tie track, compacted by traffic k = 3,000 lb/in2

Plastic composite-tie track, compacted by traffic k = 3,000 lb/in2

Concrete-tie track, compacted by traffic k = 6,000 lb/in2

Wood-tie track, frozen ballast and subgrade k = 9,000 lb/in2

These values are general approximations and it is important to note true track modulus measurements are sensitive to tie material, tie dimensions, fastening systems, tie pads, recent maintenance activities, as well as ballast and subgrade characteristics.1 Different tie materials (i.e. Concrete, Wood, or Plastic/Engineered Composite) can significantly influence the vertical response of the track. Optimization of these cross tie materials, spacing, and dimensions provide the potential to alleviate track transition problems.

1.8.2 TRACK TRANSITION PROBLEM (2006)

Stiffness transition regions are locations where a railway track exhibits abrupt changes in vertical stiffness. They usually occurat abutments of open-deck bridges, where concrete tie track changes to wooden tie track, at the ends of tunnels, at highway grade crossings, or at locations where rigid culverts are placed close to the bottom of ties. Abrupt changes in track stiffnessresult in increased dynamic wheel loading, accelerated track degradation (rail batter, surface degradation etc.), and poor ridequality. These locations have been seen to deteriorate significantly faster than regular track, and require frequent maintenance.

Direction of travel plays an important role in the method of track degradation experienced at a track transition. A train may betraveling: (1) from a region of lower stiffness to higher stiffness, or (2) from a region of higher stiffness to lower stiffness.

In Case 1, a wheel may be traveling from a softer subgrade onto a concrete bridge abutment. Here the wheel is lifted in a veryshort period of time and the abutment is subjected to increased dynamic wheel loads. The damage may be battered rails, plate cut in wood ties on top of the abutment, or even fracture of the abutment.

In Case 2, a wheel may be moving off of an open deck bridge onto a softer ballasted track. Since the softer ballasted track deflects more, the wheel drops off the abutment and generates an increased dynamic loading. The location of the impact is dependent upon train speed with higher speeds resulting in impacts further away. These impact loads will disturb the ballast and will eventually result in permanent rail deformations. The outcome is the common “dip” seen in track at the end of bridges, crossings, and tunnels.

1.8.3 TRACK TRANSITION REMEDIES AND PRACTICES (2006)

In practice, several methods have been developed to alleviate the problems associated with abrupt changes in vertical track stiffness. These methods all attempt to match vertical track stiffness whenever possible. Abrupt changes in vertical track stiffness have historically presented maintenance problems to railroads and empirical methods have been used to try to correct this problem. These methods include:

a. Gradually stiffening the approaches entering and leaving a high stiffness zone

1 A method for determining true vertical track modulus is given in Chapter 16, Article 10.11.1.




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b. Reducing the stiffness on the hard side (e.g. grade crossing) of the track

Remedies that have historically been used to gradually stiffen the soft portion of the track include a transition zone of cross ties with increasing length (usually switch ties) that gradually change the vertical track stiffness until it reaches a stiffness compatible with that of the hard portion of the track. Installing longer switch ties at open-deck bridge ends, ahead of turnouts,and at the end of concrete tie zones has proven effective at reducing the effects of the stiffness change. Also reducing tie spacing, increasing the tie width (bearing area at the ballast interface), and utilizing elastic fastening systems increase thevertical stiffness at approaches to high stiffness zones.

Other remedies target the subgrade response on the approaches. One such remedy utilizes layers of geotextile such that the thickness of the layers gradually increases towards the hard section of the track resulting in a gradual increase in track stiffness. A variation on the geotextile remedy is to use layers of hot mixed asphalt to gradually increase the vertical trackstiffness towards the stiff portion of the track. In addition to these methods, one method utilizes a concrete slab cantileveredfrom the stiff portion to the soft portion. The bending action of the cantilevered slab provides a stiffness transition zone.

The primary method used in reducing the stiffness of the hard portion of the track utilizes pads or mats to change (reduce) thestiffness of the hard portion of the track. Figure 30-1-2 shows the schematic of three pad types and ballast mat, which are commonly used to reduce track stiffness. This methodology utilizes the elastomeric properties of the pads to reduce the stiffness on the hard side of the track such that it matches the stiffness of the soft side of the track as closely as possible. By using the appropriate rail seat pad, tie plate pad, under-tie pad, or ballast mat, the hard portion of the track will have stiffnesscharacteristics that can approach those in the softer portion of the track. This will in effect provide for a constant stiffnessvalue through the crossing area.

Changing tie material from concrete to wood or plastic on open deck bridges also reduces the track modulus of the bridge span. By utilizing appropriate combinations of tie material and pad properties it is possible for bridge spans or other finitelength hard spots to closely match the stiffness of the parent track.

In addition to the two general methods described above, a third method changes the stiffness characteristics of the track superstructure (the rail itself) on the soft side of the track to alleviate vertical accelerations by reducing the transition characteristics of the track structure. This is done by adding additional lengths of rail (e.g. increasing the number of rails in a

Figure 30-1-2. Schematic of Various Pads and Ballast Mat in a Track Structure (See Reference 7)

Ties



zone from 2 to 4) to the soft side of the track. This then changes the overall stiffness characteristics of the rail on the soft side as opposed to changing the stiffness characteristics of the subgrade. This method provides the same transition characteristicsas described above.

30-2-1

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30Part 2

Evaluative Tests for Tie Systems

— 2014 —

FOREWORD

The intent of these tests is to provide basic data that can be compared to previous tie and fastener performance data and minimum performance recommendations developed by the American Railway Engineering and Maintenance of Way Association. The test results will indicate relative characteristics under similar test conditions. These tests are not to beconstrued as specifications.

The tests will provide compehensive laboratory data under likely range of environmental conditions found in North American Railroads. Other material-specific testing to evaluate tie/fastener system properties may be necessary before field-testing canbe considered.

For testing of concrete ties, the relevant sections of Chapter 30, Part 4, Concrete Ties, shall take precedence.

TABLE OF CONTENTS


2.1 Tie Performance Test Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-3

2.2 Bending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-32.2.1 Test 1A: Bending - Railseat Positive (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-32.2.2 Test 1B: Bending – Railseat Negative (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-42.2.3 Test 1C: Bending – Center Negative (2010) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-52.2.4 Test 1D: Flexural Fatigue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-8

2.3 Test 2: Rail/Plate Area Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-8

2.4 Ability to Resist. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-92.4.1 Test 3A: Embedded Shoulder/Screw Spike/Spike/Threaded Insert Pullout (2010) . . . . . . . . . . . . . . 30-2-92.4.2 Test 3B: Spike Lateral Restraint (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-10

2.5 Tie Pad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-112.5.1 Test 4A: Tie Pad Test (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-112.5.2 Test 4B: Impact Attenuation Test (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-11

2.6 Fastener . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-142.6.1 Test 5A: Fastener Uplift (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-14


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2.6.2 Test 5B: Fastener Longitudinal Restraint (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-152.6.3 Test 5C: Fastener Repeated Load (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-162.6.4 Test 5D: Fastener Lateral Load Restraint (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-182.6.5 Test 5E: Fastener Assembly Rotation (2006). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-19

2.7 Test 6: Tie and Fastener System Wear/Deterioration Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-19

2.8 Test 7: Fastener Electrical Impedance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-26

2.9 Test 8: Single Tie Lateral Push . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-26

LIST OF FIGURES


30-2-1 Rail Seat Positive Bending Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-430-2-2 Rail Seat Negative Bending Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-530-2-3 Center Negative Bending Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-630-2-4 Rail Seat Compression Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-930-2-5 Spike Lateral Restraint Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-1030-2-6 Tie Pad Attentuation Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-1230-2-7 Fastener Uplift Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-1430-2-8 Fastener Longitudinal Restraint Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-1630-2-9 Fastener Repeated Load Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-1730-2-10 Fastener Lateral Load Restraint Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2-18


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SECTION 2.1 TIE PERFORMANCE TEST DESCRIPTIONS

Except as noted in each test description, all tests will normally be conducted at ambient temperature (70o F, +/-10o F). Test reports will include the range of temperatures during testing. Information shall include rail size for which the ties are designed, the type of fastening system to be used, and how that system is to be applied. Full-size tie specimens and complete sets of rail fasteners will be needed to complete the tests.

SECTION 2.2 BENDING

2.2.1 TEST 1A: BENDING - RAILSEAT POSITIVE (2006)

a. Test Purpose:

Determines railseat positive flexural bending performance.

b. Test Frequency:

Initial qualification and routine testing required.

c. Test Procedure/Setup:

1A. Bending - Railseat Positive Determines railseat positive flexural bending performance.1B. Bending - Railseat Negative Determines railseat negative flexural bending performance.1C. Bending - Center Negative Determines center negative flexural bending performance.1D. Flexural Fatigue Indicates the ability to withstand repeated vertical loads.1E. Ultimate Load Test Determines ultimate strength capacity of the tie.2. Rail/Plate Area Compression Determines ability to resist railseat loads.3A. Embedded Insert Pullout Determines ability to resist withdrawal for the fastening system.3B. Spike Lateral Restraint Determines ability of a spike or similar fastener to resist lateral

movement.4A. Tie Pad Test Determines load-deflection properties of the tie pad.4B. Tie Pad Attenuation Test Evaluate the attenuation of impact loads on ties.5A. Fastener Uplift Determines rail-to-tie holding forces.5B. Fastener Longitudinal Restraint Determines ability of fastening system to resist longitudinal rail

movement.5C. Fastener Repeated Load Determines ability of fastening system to withstand vertical and lateral

loads.5D. Fastener Lateral Load Restraint Determines ability of fastening system to resist lateral loads.5E. Fastener Assembly Rotation Determines ability of tie and fastener assembly to resist forces as a result

of tie skewing.6. Wear/Abrasion Fatigue test to determine rail seat abrasion or deformation resistance due

to repeated loads.7. Electrical Impedance Determines ability of tie system to resist conducting electrical currents.8. Single Tie Lateral Push Determines ability to resist movement perpendicular to rail (lateral

stability) in track structure.


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P = load required to produce the specified rail seat bending moment. Load is to be applied through a spherical loading system perpendicular to the tie base.

NOTE: The Elastomeric Supports will be 5-1/2" x width of rail seat, 1" thick and 50 Shore A durometer. Other materials may be substituted for the rubber supports shown, by agreement with the Engineer.

For prestressed concrete monoblock ties:

(1) With the tie supported and loaded as shown above, a load increasing at a rate between 3 and 10 kips per minute shall be applied until the load (P) is obtained.

(2) This load shall be held for not less than 3 minutes, during which time an inspection shall be made to determine if structural cracking occurs. A structural crack is a crack originating in the tensile face of the tie, extending to the outermost level of reinforcement or prestressing tendons and which increases in size under application of increasing load.

For other ties, a custom-designed fixture shall be used. The support and loading characteristics for the custom-designed fixture must be comparable. Test procedure and set-up shall be verified and agreed with the Engineer.

d. Test Criteria:

Refer to Section 4.4 and Section 4.9 for flexural strength requirements for prestressed concrete monoblock ties. For ties of other materials, the flexural requirements are under development.

2.2.2 TEST 1B: BENDING – RAILSEAT NEGATIVE (2006)

a. Test Purpose:

Determines railseat negative flexural bending performance.

NOTE: Required for all tie materials unless flexural capacity is the same in both positive and negative directions.

b. Test Frequency:

Figure 30-2-1. Rail Seat Positive Bending Test


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Initial qualification testing only.

c. Test Procedure / Setup:

P = load required to produce the specified rail seat bending moment. Load is to be applied through a spherical loading system perpendicular to the tie base. Load location should be centered between any fastener system inserts embedded in the top surface of the tie.

NOTE: The Elastomeric Supports will be 5-1/2” x width of rail seat, 1” thick and 50 Shore A durometer. Other material may be substituted for the rubber supports shown, by agreement with the Engineer.

For prestressed concrete monoblock ties:


(2) This load shall be held for not less than 3 minutes, during which time an inspection shall be made to determine if structural cracking occurs. A structural crack is a crack originating in the tensile face of the tie, extending to the outermost level of reinforcement or prestressing tendons and which increases in size under application of increasing load.


d. Test Criteria:

Refer to Section 4.4 and Section 4.9 for flexural strength requirements for prestressed concrete monoblock ties. For ties of other materials, the flexural requirements are under development.

2.2.3 TEST 1C: BENDING – CENTER NEGATIVE (2010)

a. Test Purpose:

Determines center negative flexural bending performance.

Figure 30-2-2. Rail Seat Negative Bending Test


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NOTE: A Center Positive Bending test based on the same test configuration will be required if there are significant differences between the properties of the top and bottom center of tie.

b. Test Frequency:

Initial qualification and routine testing required.


P = load required to produce the specified rail seat bending moment. Load is to be applied through a spherical loading system perpendicular to the tie base.

NOTE: The Elastomeric Supports will be 5-1/2” x width of rail seat, 1” thick and 50 Shore A durometer. Other material may be substituted for the rubber supports shown, by agreement with the Engineer.

For prestressed monoblock ties:


(2) Load (P) shall be held for not less than 3 minutes, during which time an inspection shall be made to determine if structural cracking occurs. A structural crack is a crack originating in the tensile face of the tie, extending to the outermost level of reinforcement or prestressing tendons and which increases in size under application of increasing load.

(3) Measure the deflection of the center of tie relative to the vertical support.


For Engineered Polymer Composite Ties:

(1) With the tie supported and loaded as shown in Figure 30-2-3 above, a load shall be applied at a deflection rate of five (5) inches (127 millimeters) per minute.

Figure 30-2-3. Center Negative Bending Test


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NOTE: Fo rmore complete characterization of the mechanical properties of polymer composite ties, manufacturers are encouraged to perform additional bending tests at deflection rates of one (1) inch (25mm) per minute and at ten (10) inches (250mm) per minute.

(2) Measure the deflection of the center of the tie relative to the tie directly above the tie supports thirty (30) inches (760mm) each side of the loading centerline.

(3) Record load and deflection throughout the test.

NOTE: If measuring Modulus of Elasticity (MOE) only, load the tie until a minimum 1% strain is achieved.

(4) Calculate MOE using the following equation:

MOE = mL3 / 48I where:

m = slope of the load-deflection curve (pounds/inch), figured as the straight line from the origin (corrected for toe effect) to the load generating 600 pounds per square inch (psi) stress

L = loading span, (inches)

I = 1/12 (bd3)

b = tie width (inches)

d = tie height (inches)

(For a nominal seven (7) inch by nine (9) inch tie, MOE (psi) = 17.493m.)

NOTE: In a typical stress-strain curve, there is a toe range that does not represent a property of the material. Toe effect is caused by the slack and alignment or seating of the specimen during testing. Correction for this toe effect shall be performed per Annex A.1 of ASTM Test Method D6109.

(5) Calculate Modulus of Rupture (MOR) using the maximum stress in the outer fibers at the moment of break.

MOR = 3LP / 2 bd2 where:

P = the applied load at break (lbf)

L = loading span, (inches)

b = tie width (inches)

d = tie height (inches)

(For a nominal seven (7) inch by nine (9) inch tie, MOR (psi) = 0.204P.)

(6) A minimum of five (5) tests shall be replicated and the results reported as an average.

d. Test Criteria:

Refer to Section 4.4 and Section 4.9 for flexural strength requirements for prestressed concrete monoblock ties.

For wood ties, refer to article “Proposed Strength Properties Test for Wood Crossties” by Chow, Reinschmidt, Davis, Laine, Choros and Kalay.


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For engineered composite ties, refer to Section 5.3.3, Table 30-5-1 for minimum values.

2.2.4 TEST 1D: FLEXURAL FATIGUE

a. Test Purpose/Scope:

Indicates ability to withstand repeated vertical loads resulting in bending.

b. Test Frequency:



For prestressed monoblock ties:

(1) Following the vertical load test for positive moment (i.e., refer to set-up for Test 1A), the load shall be increased at rate of 5 kips per minute until the tie is cracked from its bottom surface up to the level of the lower layer of reinforcement.

(2) After removing the static rail seat load necessary to produce cracking, substitute ¼ in. thick plywood for the rubber loading pads. Subject the tie to 3 million cycles of repeated loading with each cycle varying uniformly from 4 kips to the value of 1.1P. The repeated loading shall not exceed 600 cycles per minute.

NOTE: P = load required to produce the specified rail seat moment in Section 4.4


d. Test Criteria:

For prestressed concrete monoblock ties, the requirements of this test will have been met if the tie can support the rail seat load (1.1P) after the application of 3 million cycles.

For ties of other materials, strength requirements are under development.

SECTION 2.3 TEST 2: RAIL/PLATE AREA COMPRESSION

a. Test Purpose:

Determines ability to resist railseat loads.

NOTE: This test is applicable only to tie materials where material compression in the railseat area may affect performance.

b. Test Frequency:



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(1) Load rail seat area for proposed fastening system. The size of the loading plate should be 7-3/4”x14”x1”.

(2) Load to 100 kips compression in increments of 20 kips in greater than 30 seconds and less than 60 seconds between increments.

(3) Record load and deflection values at each increment.

d. Test Criteria:

Maximum elastic deformation at 100 kips is ¼ inch.

Maximum permanent deformation at recovery after release of load is 1/8 inch within one minute after release of load.

SECTION 2.4 ABILITY TO RESIST

2.4.1 TEST 3A: EMBEDDED SHOULDER/SCREW SPIKE/SPIKE/THREADED INSERT PULLOUT (2010)

a. Test Purpose:

Determines ability to resist withdrawal for the rail fastening system.

b. Test Frequency:



Figure and test details to be finalized.

Figure 30-2-4. Rail Seat Compression Test


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For embedded shoulders for concrete ties, refer to Article 4.9.1.9 for test setup. An axial load of 12 kips shall be applied to each insert separately and held for not less than 3 minutes.

For spike pullouts in wood and composite ties, a 5/8-in. square and 6-1/2 in. long spike will be driven in 4.5 in. The pullout load will typically be applied at a loading rate of approximately 1 in. per minute. However, some pullout loads have been applied at loading rates of 0.3 to 2.0 in. per minute.

d. Test Criteria:

Refer to Article 4.9.1.9 for concrete ties.

For spike pullout, test criteria to be determined.

For engineered composite ties, refer to Section 5.3.3, Table 30-5-1 for minimum values for both cut spikes and screws.

2.4.2 TEST 3B: SPIKE LATERAL RESTRAINT (2006)

a. Test Purpose:

Determines ability of a spike, screw spike, or similar fastener hold down to resist lateral movement.

b. Test Frequency:



(1) Spike will be driven in to the tie to their normal installation working depth.

(2) Deflect lateral to 0.2 inch at rate of 0.2 inch per minute.

(3) Record load / deflection curve and maximum load.

d. Test Criteria:

Figure 30-2-5. Spike Lateral Restraint Test


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To be determined.

SECTION 2.5 TIE PAD

2.5.1 TEST 4A: TIE PAD TEST (2014)

a. Test Purpose

Determines load-deflection properties of the tie pad.

b. Test Frequency:

Initial qualification testing only. It is recommended that this test be conducted for pad temperatures of –45, 70, and 140°F, +/- 5°F.


Figure to be finalized.

(1) The tie pad shall be loaded vertically in a fastener system using an appropriate rail section, or as a plain pad.

(2) A cyclic load varying from 4 kips to 30 kips shall be applied continuously at a rate of 4 to 6 cycles per second for a total of 1,000 cycles.

(3) A static load shall be applied, at a rate between 3 and 6 kips/min (13.4 and 26.7 kN/min) in increments of 1 kip (4.45 kN) up to a maximum of 50 kips (223 kN). For each load increment, vertical pad deflection shall be measured to the nearest 0.0001 inch (0.0025 mm) and recorded values for vertical load versus deflection shall be plotted on a graph. Spring rate shall be calculated by the slope of the line connecting the points representing pad deflections at 24 and 44 kips (107 kN and 196 kN) for heavy axle loading and 4 and 20 kips (18 kN and 89 kN) for medium axle loading.

(4) Load shall be released and pad deflection and temperature recorded 10 seconds after load removal.

d. Test Criteria

Refer to Article 4.9.1.15 for concrete ties.

2.5.2 TEST 4B: IMPACT ATTENUATION TEST (2014)

a. Test Purpose:

The test is used for comparing the attentuation of impact loads on ties by different rail pads. The test is applicable to ballasted track and the complete fastening system.

b. Test Frequency:


c. Test Setup

This test compares attenuation properties of pad designs to a reference 5 mm Amtrak EVA flat pad manufactured with Dupont Elvax 660 (or equivalent) with a relative pad stiffness not to be less than 2850 kip/in. If the pad to be tested is


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of a thickness other than 5 mm, the difference shall be made up by the use of an aluminum plate, to be placed between the rail and the pad.

An uncracked concrete tie, made without modification for this test, of the correct rail seat dimensions for the fastening system shall be used. The mass of the tie shall be recorded. The tie should have two resistance strain gauges of 4 to 4-3/4" gauge length bonded to the tie on the centerline of the rail seat. The strain gauges shall be oriented parallel to the base of the tie. One gauge should be as close as possible to the rail seat, but avoiding any edge chamfer or radius, and the second should be at least 3/8" but not more than 1" above the base of the tie. See Figure 30-2-6.

Before proceeding with the attenuation test, the tie should have been previously subjected to a railseat positive bending test as described in Article 2.2.1. The upper and lower strain gauge values at load P, as defined in Article 2.2.1 should be recorded as the tie static strains. These values shall be used later for the purpose of test integrity validation. It is acceptable to reuse these static strain values in the case that multiple tests may performed on the same tie.

The tie support should consist of a bed of crushed stone with a particle size of 0.200" to 0.600" contained in a tank.The support should permit a vertical deflection of the tie of 0.004" to 0.020" when the tie is subjected to an increase in static load from 11,200 to 13,500 lbf at one rail seat. If the specification is not met the ballast should be replaced and the calibration process should be carried out before any further testing is performed. Alternatively, the support may consist of a rubber mat on a firm base which exhibits the same vertical deflection properties as previously defined.

A 12" length of rail of the appropriate section required for the fastening system to be tested shall be used.

The combination of drop mass and drop height should be such that the applied impact is less than 80% of the static strain of the tie, as recorded previously. The time interval for the strain gauge output of first impulse of load should be 1 to 5 ms. If these parameters are not achieved the drop mass and drop height should be adjusted to ensure compliance.

The static stiffness of a 5 mm thick EVA reference pad should be measured as described in Article 2.5.1 to ensure that the reference pad to be used has a stiffness of not less than 2,850 kip/in.

d. Test Procedure:

The fastening system to be tested should be constructed using the EVA reference pad previously tested for static stiffness. The fastening system should be subjected to a total of ten impacts, and the upper and lower strain gauge values averaged and recorded as the mean peak strain. A mean value shall be calculated for the mean strains of the ten impacts.

Figure 30-2-6. Tie Pad Attentuation Test


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The test on the EVA pad should then be carried out again, and the result compared to that which was previously calculated. If this result is within ±10% of the mean value, then the result can be accepted and used in the measurement of the fastening system to be tested.

If the result is not within the 10% limit then the test conditions should be adjusted and the test repeated until this criterion is met.

The EVA pad should then be replaced with the new test pad.

The fastening system with the new test pad should then be subjected to five impacts, the results of which should be discarded.

The fastening system should then be subject to a further three impacts with the peak strain gauge values recorded for each impact.

The impact attenuation at the top and bottom of the tie shall be calculated for the test pad relative to the reference pad for each of the three measured impacts. The following method shall be used, where symbols are defined as:

a impact attenuation; reduction in tie strain of test pad vs. reference pad

at percent attenuation at top of tie

ab percent attenuation at bottom of tie

�pt first peak strain at top of tie; test pad

�pb first peak strain at bottom of tie; test pad

�prt first mean peak strain at top of tie; reference pad

�prb first mean peak strain at bottom of tie; reference pad

The test result will be reported as the mean attenuation value of the three recorded impacts using the test pad.

e. Test Validation (Tie Condition):

at 100 1epteprt---------– %=

ab 100 1epbeprb----------– %=

aat ab+

2--------------------%=


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To accept the test results the ratio between the top and bottom strain gauges should be calculated for the test samples.This ratio should be compared with the static ratio as detailed previously and recorded in Article 2.5.2.c. If the ratio between the top and bottom strain gauges during the dynamic tests is within 10% of the value recorded for the static test then the results can be accepted. If these criteria are not met then the results must be rejected and cannot be reported.

In this case the tie should be replaced, and the tie acceptance procedure carried out to verify the new tie.

The testing of the unknown fastening system should then be repeated.

f. Test Criteria:

To be agreed upon by the purchaser and supplier.

SECTION 2.6 FASTENER

2.6.1 TEST 5A: FASTENER UPLIFT (2014)

a. Test Purpose

Determines rail to tie holding force.

b. Test Frequency



Figure 30-2-7. Fastener Uplift Test


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Part A:

(1) An 18 to 20 inch piece of rail shall be secured to one rail seat using a complete rail fastening assembly (i.e., pad, bolts, clips and associated hardware as recommended by the manufacturer of the rail fastening system).

(2) In accordance with the loading diagram shown above, a load at a rate not greater than 1 kip/min shall be applied to the rail.

(3) The load P perpendicular to the rail base at which separation of the rail from the pad or the pad from the rail seat (whichever occurs first) shall be recorded.

Part B:

(4) The load shall then be completely released.

(5) A load of 1.5P (not to exceed 10 kips) shall then be applied and separation gap measured.

(6) Release load.

(7) Reload to separation gap and record load “P2” for comparison per permanent set.

d. Test Criteria:

For all ties using elastic fasteners, the inserts shall not pull out or loosen in the concrete and no component of the fastening system shall fracture nor shall the rail be released.

For other tie materials, test criteria to be determined.

2.6.2 TEST 5B: FASTENER LONGITUDINAL RESTRAINT (2006)

a. Test Purpose:

Determines ability of fastening system to resist longitudinal rail movement.

b. Test Frequency:




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(1) This test shall be conducted both before and after the Fastening Repeated Load Test (refer to Test 5C). This test shall be conducted without disturbing the rail assembly in any manner.

(2) A longitudinal pull load shall be applied (as shown above) in increments of 0.4 kips with readings taken of longitudinal rail displacement after each increment. The load shall be applied in a direction coinciding with the longitudinal axis of the rail.

(3) The rail displacement readings shall be the average of two dial indicator readings measured to 0.001 inch. The dial indicators shall be placed on each side of the rail with plungers parallel to the longitudinal axis of the rail.

(4) The load shall be increased incrementally until a load of 2.4 kips is reached. This load shall be held for not less than 15 minutes.

d. Test Criteria:

The rail shall not move more than 0.20 inch during the loading and initial 3 minute period. There shall be no more than 0.01 inch rail movement after the initial 3 minutes.

The fastening shall be capable of meeting the requirements of this test in either direction.

2.6.3 TEST 5C: FASTENER REPEATED LOAD (2014)

a. Test Purpose:

Determines ability of fastening system to withstand vertical and lateral loads.

b. Test Frequency:

Figure 30-2-8. Fastener Longitudinal Restraint Test


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(1) An 18 to 20 inch piece of rail shall be secured to one rail seat using a complete rail fastening assembly (i.e., pad, bolts, clips and associated hardware as recommended by the manufacturer of the rail fastening system).

(2) Determine the load P that will just cause separation of the rail from the rail seat pad or the pad from the rail seat whichever occurs first. This load may be determined during the Fastening Uplift Test 5A described in Article 2.6.1 in which case a new set of fastening clips shall be used for the repeated load test.

(3) In accordance with the loading diagram above, alternating downward and upward loads shall be applied at an angle of 20 degrees to the vertical axis of the rail for 3 million cycles. The loading frequency shall not exceed 300 cycles per minute. The rail shall be free to rotate under the applied loads. One cycle shall consist of both a downward and an upward load.

(4) The magnitude of the upward load shall be 0.6P, where P is the load determined in paragraph (2). If springs are used to generate the upward load, the downward load shall be 30 kips (133.5 kN) plus 0.6 P. If a double-acting hydraulic ram is used to generate both the upward and downward load, the downward load shall be 30 kips (133.5 kN).

Figure 30-2-9. Fastener Repeated Load Test

M = FOR DETERMINATION OF P SEE Article 2.6.1


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(5) This repeated load test may generate heat in elastomeric rail seat pads. Heat build-up in such pads must not be allowed to exceed 140°F (71°C). Heat build-up can be controlled by reducing the frequency of load application or by providing periods of rest to allow cooling of the pad to take place.

(6) Retorquing of threaded elements before the completion of 500,000 cycles of loading shall not be permitted without the written approval of the Engineer.

d. Test Criteria:

Rupture failure of any component of the fastening system shall constitute failure.

2.6.4 TEST 5D: FASTENER LATERAL LOAD RESTRAINT (2006)

a. Test Purpose:

Determines ability of fastening system to resist lateral loads.

b. Test Frequency:



(1) A suitable length of new rail (of the size to be used in track) shall be secured to one rail seat using a complete rail fastening assembly (i.e., pad, bolts, clips and associated hardware as recommended by the manufacturer of the rail fastening system).

(2) The entire assembly is supported and loaded in accordance with the above loading diagram. The loading head is to be fixed against translation and rotation. The wood block shall be 10” x 10” x ¾” thick 5 ply, exterior grade plywood.

(3) A preload of 20 kips is to be applied to the rail to seat the rail in the fastening. Upon release of the preload, a zero reading is to be taken on the dial indicators which measure rail translation.

Figure 30-2-10. Fastener Lateral Load Restraint Test


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(4) Load is to be applied at a rate not to exceed 5 kips per minute until either 41 kips has been applied or the rail base has translated 1/8 inch, whichever occurs first.

(5) With all load removed from the rail, a roller nest is placed between the fixed loading head and the wood block on the rail head. The roller nest shall not offer resistance to lateral movement of the rail head.

(6) After taking zero reading on the dial indicators (which measure gage widening and rail translation), a load of 20.5 kips shall be applied at a rate not to exceed 5 kips per minute.

d. Test Criteria:

Inability of the fastening system to carry the 41 kip load with 1/8 inch or less of rail translation shall constitute failure. Complete failure of any component of the tie or fastening is cause for rejection.

Rail rotation (i.e., gage widening less rail translation) greater than ¼ inch shall constitute failure of this test.

2.6.5 TEST 5E: FASTENER ASSEMBLY ROTATION (2006)

a. Test Purpose:

The in-place torsional resistance of a fastening system directly affects the frame strength of the track structure. This is the strength of the rail/tie system, with the rails acting as the longitudinal frame members and the cross ties as the cross members. The fastening systems act as torsional springs in the plane of the track structure, which in turn affects the overall lateral stability of the track.

b. Test Frequency:



The test setup is shown below. A single rail seat is assembled on a tie with a complete rail fastening assembly and a short length of rail (3 foot minimum). A couple consisting of two loads (P) is applied about the center of the rail seat. Rotation of the rail relative to the tie and to the tie plate (if used) shall be recorded as load P is varied from zero to 2,000 lb ? Load P shall be applied in 400 lb increments and held for one minute per increment. For asymmetric fastening systems, the load shall be repeated in both directions of rotation.

d. Test Criteria:

Normally the system will exhibit two ranges of rotational stiffness. These two ranges represent pre and post engagement of the rail against the fastening system. The second range of rotational stiffness for in-place torsional resistance shall normally fall in the range of 3,000 to 5,000 in.-kip/radian. There shall be no failure, cracking, or yielding of any components in the assembly after the maximum load (P) of 2,000 lb is applied and held for one minute.

Data shall be plotted to show rail rotation about the fastening system and about the tie as a function of load P. Separate data points for the start of the one minute hold and the completion of the one minute shall be plotted to indicate stability under the load.

SECTION 2.7 TEST 6: TIE AND FASTENER SYSTEM WEAR/DETERIORATION TEST

a. Test Purpose:


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Fatigue test to determine rail seat deterioration and fastener system performance in heavy axle load environments (gross rail car weight between 286,000 and 315,000 lbs.) due to repeated loads.

b. Test Frequency:

Initial fastener and tie system qualification testing or for component evaluations as required. If any individual component comprising the system is changed or modified, it is recommended that this test be repeated.


NOTE: This test apparatus and procedure is recommended to evaluate the performance of all types of tie and fastener systems.

(1) New 141RE rail shall be used for this test. The length of the rail shall be 18" (+/-6"). Rail to be centered on the fastening system.

(2) Deflection measurement locations shall be required at points 1, 2, 7, 8 (gauge side) and may also be placed at points 3 to 6 as required. Deflection measurement points will be set 5" on each side of the center line of the fastening system.

(3) The test machine consists of a load frame with a servo-controlled dual action hydraulic actuator. The load is distributed through two load arms set at an angle of 27.5 degrees from vertical. The load is transmitted equally to each railhead of a full tie using the appropriate fastening system. Alternatively, a single railseat can be used. See Load Diagram.

Figure 30-2-11. Test Example


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4(4) The load applied through the actuator to simulate conditions for tangent or shallow curves is 50,000 lbs. Based on

this load, the load distribution per rail seat is 25,000 lbs. vertical and 13,000 lbs. lateral (with L/V ratio=0.52).

(5) The load applied through the actuator to simulate conditions for severe service testing (i.e., curves greater than 5 degrees) is 65,000 lbs. Based on this load, the load distribution per rail seat is 32,500 lbs. vertical and 16,900 lbs. lateral (with L/V ratio=0.52).

(6) A reverse lateral action load of 1,000 lbs. (1,000 on each individual rail) must be applied to the rails at field side base of the rail with the use of a device to maximize repeated rail base travel to simulate actual field conditions.

(7) An abrasive environment must also be simulated on each rail seat. Water drip nozzles are positioned over the field and gage sides of each rail seat. Clean, dry sand is spread on both sides of the rail seat. Apply sand above the insulator (which is above the clip). Water should carry the sand between the insulator and the rail and the insulator and the shoulder. (Note: For concrete ties, the cyclic loading will simulate hydraulic action which draws the abrasive laden water under the pad to introduce the abrasive medium.)

Figure 30-2-12. Load Diagram


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(a) The sand should be Ottawa White Sand consisting of 99.5% minimum SiO2, 7 Mohs Hardness, Specific Gravity of 2.65 and Bulk Density of 100 #/ft3 (ASTM C778) specifications. Apply a minimum of 2 teaspoons (0.333 oz.) per rail seat (50%/side) daily, but within a range between 170,000-260,000 cycles.

(b) Water: 1.25oz (+/-0.25 oz.) of tap (potable water) per access point per hour by continuous drip. Two drip points per rail seat are needed. Each water point is above the insulator to access to rail base and insulator. This is repeated for each side of the rail.

(8) Temperature environments will be simulated on each rail seat. Measure temperature under the base of rail adjacent to tie pad.

(a) For low temperature: a small chamber is built around the rail seat. The chamber is filled with dry ice. The component temperature is monitored with thermocouples. (Note: Typically, the temperature is allowed to drop to –40 degrees F. while the fatigue test runs. When the components reach –40 degrees F. the dry ice is then removed from the chamber which will allow the components to return to room temperature.) Repeat daily within a range between 170,000-260,000 cycles. Operate at a minimum of an hour at room temperature before going to the heating step.

(b) For upper temperature allow the components to return to room temperature, apply heat as necessary to allow pad to reach 135 +/-5 degrees F. for an hour. Use a radiated heat lamp if necessary. Remove heat source and return to normal testing temperature. Repeat daily within a range between 170,000-260,000 cycles.

(c) The components are visually checked without disassembly for any sign of damage which may have resulted from the combined effects of fatigue loading and extreme temperature.

(d) The following temperature cycle loading may be followed:

1 Day 1 - No temperature cycles are introduced to ensure that test and components settle in properly and no premature failures occur.

2 Day 2 - Apply cold cycle, then Room Temperature (defined as 70 degrees F +/- 20 degrees F) for one hour, heat cycle, and them Room Temperature for one hour.

3 Day 3 - Room Temperature.

4 Day 4 - Repeat cold and heat cycles as in 2.

5 Day 5,6,7 - Room Temperature.

6 Day 8 Repeat cold and heat cycles as in 2.

7 Continue rotation until testing is completed.

(9) See Deflection measurement drawing above. To measure static and dynamic head displacements during the test, a displacement transducer is placed behind the railhead on each rail seat. Deflections are monitored at regular (500,000 cycles minimum) intervals and tracked throughout the test to ensure there is no excessive movement to track the displacement trends. (i.e., consistent head deflection measurements that exceed 0.200"). Additional deflection measurements (e.g., base vertical, base lateral, gauge side vertical) can be taken by adding transducers to the assembly.

(10) Attach all test ties (concrete, wood, steel, synthetic, plastic, etc.) by direct fixation to the base of the testing assembly. This can be done with cementitious material.

(11) For concrete tie assemblies, the following pre-test procedures should be performed:


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(a) Prior to assembly, the test tie rail seat area is cleaned to ensure that nothing will interfere with the fastener assembly. For reference, the rail seat is photographed in the pre-tested condition. The rail seat is also inspected for air holes, ridges or uneven surfaces. If any anomalies are apparent during this inspection, the Engineer is notified and a course of action is recommended. This usually involves minor repairs to fill air holes or to level the surface. Measure the rail seat profile to reflect contour and provide base for reference and wear. Use a measuring instrument similar to the one shown above and measure a minimum of nine points.

(b) If the tie cannot be repaired satisfactorily, an alternate tie is used.

(c) Prior to installation, the components to be installed on each seat are inspected. Pad thickness measurements are taken in three locations along the field side rail edge, through the middle and on the gauge side rail edge of each pad. Each insulator is measured at three locations on the post and one location in the clip bearing area. The position of all components is to be logged for orientation and kept in the same position. If a component fails then report the failure to party requesting the test and determine if testing should continue. When testing fastening systems, no components are to be replaced or reversed. When performing tie wear tests and the fastening is not under evaluation, then the components may be reversed and replaced. Report all reversals and replacements and at what point (X cycles) during the cyclic loading count.

1 Recommend that median tolerance components be selected. Report the median dimension versus each actual measurement. The party requesting the testing needs to understand that tight fitting components will perform better than loose fitting components but median components should be used.

2 Measure adjacent shoulder distance for mean compliance. If using the entire tie measure out to out. If testing just one rail seat then double the effective gauge widening displacement.

3 Verify the taper of shoulder face.

Figure 30-2-13. Measuring Instrument


Ties



4 Measure and report the angular rotation (plan view) of each shoulder with respect to longitudinal axis of the tie.

5 Report clip reaction point elevation of shoulder and median height.

6 Measure the insulator width and thickness (both ends and middle).

7 Measure pad thickness or rail pad assembly (set thickness) at nine locations per rail seat. These locations shall be at approximately the same location as the measurements of the railseat in (11)(a) above.

8 Measure pad assembly components durometer(s) (ASTM D2240).

9 Pads - Record temperature of the pad.

• Determine temperature. Assure temperature does not exceed 140 degrees F. Add a fan if necessary to reduce temperature.

• Take temperature under base of rail adjacent to tie pad using a thermocouple.

• If a rubber tie pad is being tested then assure that rail testing temperature meets the heat cycle testing above.

10 The insulator manufacturer shall provide properly and equally conditioned insulators. The lab shall report the weight of each insulator and compare that weight with the manufacturer’s recommended weight.

11 Clip toe load measured and reported. Use a 0.006 vertical movement of the rail to equate toe load. (subtract rail weight)

12 The Concrete Surface Profile (As shown in the ICRI guideline 03732) shall be reported at the beginning of the test and at the conclusion of the test.

13 The following information regarding concrete properties shall be reported to the customer by the tie manufacturer.

• Compressive Strength.

• Aggregate Type - report per ASTM C295.

• Tie cast date.

• Water to total cementitious content ratio.

• SSD mix design per yard.

• Splitting tensile strength ASTM C496.

• Results of ASTM C779 c.

(d) If loose steel abrasion plates or equivalent underlayment pads are used, they must be inspected for defects or cracks that may influence the test results. They are then measured in the same locations as the pads and positioned on each rail seat.


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(e) To complete the assembly, the pads are placed on each rail seat and checked for correct positioning. The test rails are placed on the tie pads and the insulators are positioned on the rail bases, adjacent to the shoulders.Clips are then installed.

(12) For wood or engineered composite tie assemblies, the following pre-test procedures should be performed:

(a) The tie is inspected to ensure that there are no serious defects such as cracks, checks or knots that would adversely affect the results of the test. For example, a plate-cutting test should not be run on a rail seat that contains a knot because uneven wood hardness can cause premature plate cracking.

(b) Plates are fastened to the tie per manufacturer’s specifications using the appropriate hold down devices (e.g., cut spikes for standard tie plates, track screws for rolled steel and cast tie plates). Rails are positioned and fastened in place.

(c) Record the cross-section dimensions of the tie and any special preparation.

(d) Measure temperature. Assure temperature does not exceed 140 degrees F. Add a fan if necessary to reduce temperature.

(13) For steel tie assemblies, the following pre-test procedures should be performed:

(a) An alternative means of support may be a ballast box. If used, a ballast box is installed on the test bed and filled with 12" (300mm) of standard grade track ballast. The ballast should be “hilled” up in the center of the box to ensure that ballast is evenly distributed under the tie. Use mechanical brackets to stabilize the box on the test table.

(b) The tie (with rails fastened using the appropriate fasteners) is placed on the “hilled” ballast and tamped in place.

(c) Run the test setup briefly (e.g., 25 to 50 cycles) to settle the ballast. Then backfill the tie to ensure that the ballast is level with the top surface of the tie.

(14) After completing the pre-test procedures (i.e., the fully-assembled tie is set up in the fatigue load frame), a head deflection measurement under static load is taken to establish a benchmark. When applying maximum load, check data recorders for the measured head displacement.

(15) After completing the static load measurement, run the wear / abrasion test. This test should be run for at least 3,000,000 cycles (or until failure) at a frequency of 2.5 Hz (+/-20%). This repeated load may generate heat in the elastomeric rail seat pads or composite ties. Heat build-up in such pads or composite ties must not be allowed to exceed 140 degrees F. Normal testing temperatures range from 35 - 100 degrees F. Heat build-up can be controlled by reducing the rate of load application or by providing rest periods to allow the pad to cool. A fan may be used to reduce testing temperature.

(a) Additional measurements requiring stop and tear down of the system may be performed. Report such results as appropriate.

(16) Prior to and upon completion of the wear / deterioration test, the rail seat assemblies should be examined and photographed. Static load deflection test should be repeated. Any anomalies should be documented. The fastening systems on each rail seat should then be disassembled. The components should be re-measured. The components should be examined for signs of failure / damage. The rail seat deterioration maximum depths should be measured. The rail seat should be examined for signs of damage. Any further anomalies should be documented.

d. Test Criteria:


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Test failure occurs when an individual component “breaks” or when rail deflections on any measurement point described in c (2) is greater than 0.2”. This test gives relative results to a control standard on one rail seat of the test tie.

SECTION 2.8 TEST 7: FASTENER ELECTRICAL IMPEDANCE TEST

a. Test Purpose:

Determines the ability of tie and fastener system to resist conduction electrical currents under wet conditions.

b. Test Frequency:

Initial qualification testing and routine testing required.


(1) Two suitable lengths of rail (greater than the width of the tie) shall be secured to the two rail seats using a complete rail fastening assembly (i.e., pad, bolts, clips, and associated hardware as recommended by the manufacturer of the rail fastening system).

(2) The complete tie and rail assembly shall be immersed in water for a minimum of 6 hours. At the start of each test, the water shall exhibit an electrical resistance value between 1,000 and 1,500 ohms.

(3) Remove the tie and rail assembly from the water, and perform the remainder of the test procedure at room temperature within 1 hour.

(4) Clean contact point on each rail, ensuring that contact points are free from rust or other contaminants, and attach test cables.

(5) Apply 10 volts AC 60-Hertz potential between the two running rails for a period of 15 minutes.

(6) Measure the current flow between the two rails.

(7) Calculate the impedance by dividing the applied 10 volts by the current flow in amperes.

d. Test Criteria:

An impedance of 10,000 ohms is considered sufficient to provide trouble-free operation of track signal systems. Ties with values even lower than 10,000 ohms are known to still be functional within signal systems. Acceptance of ties with impedance lower than 10,000 ohms, or for an impedance requirement greater than 10,000 ohms, shall be agreed upon between buyer and seller.

SECTION 2.9 TEST 8: SINGLE TIE LATERAL PUSH

a. Test Purpose:

Determines ability of a tie to resist movement perpendicular to rail (lateral stability).

b. Test Frequency:

Performance testing for research and comparison purposes.



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Figure and test details are under development.

(1) The test section shall be selected at a track location where a minimum of three ties of the same type being evaluated are installed consecutively in a standard fashion. The installation should include complete fastening, tamping the ballast and regulating / dressing the ballast at the ends of the tie and with clean ballast at or above 40oF. Ambient temperature shall not be at or above neutral rail temperature.

(2) The middle tie of the three consecutive ties shall be the tie to be tested.

(3) The test apparatus will be a hydraulic piston and a steel angle bracket (i.e., reaction bracket) that can be fastened to the tie. The piston shall be of sufficient size to exert a minimum of 10,000 lbf. and shall have a minimum extension of 3 inches. The hydraulic mechanism shall have a readout that will display the maximum load reading (i.e., pounds force being applied).

(4) The reaction bracket shall be fastened to the tie. For concrete ties it can be attached to the tie shoulders. For wood/composite ties, it can be fastened to the tie using ½ inch diameter by 2-1/2 inch long lag screws. The wood/composite tie must be predrilled before installing the lags.

(5) The reaction bracket must be positioned so the piston in its unextended state fits between it and the web of the rail and will provide for a minimum 2 inches of travel of the piston.

(6) Once the reaction bracket is fastened, remove the rail fasteners for the test tie and remove the tie plates from between the rail and the test tie. Being careful not to disturb the ties.

(7) Remove the fasteners from several ties (at least 3 to 5) on either side of the test tie.

(8) Using track jacks which are placed one crib away from the test tie, raise both of the rails to a sufficient height to ensure that the test tie will not contact the rails when being pushed out.

(9) Place the piston between the reaction bracket and the web of the rail and jack the piston until initial contact is made.

(10) Position a measuring device so the distance that the test tie moves can be recorded.

(11) After ensuring that the load readout is reset, continue jacking the piston in a uniform manner until the load either remains constant or starts to fall.

(12) Record the maximum force to push out the test tie (to the nearest 50 lbf.). Record the approximate distance the test tie traveled when this maximum force was achieved. Record width of shoulder, MGT since last ballast disturbance, tie type, age, and condition.

(13) Prepare a load-deflection graph for the measured results.

(14) Once the test is completed, the test tie should be pushed back into its original position.

d. Test Criteria:

For engineered composite ties, refer to Section 5.3.3, Table 30-5-1 for minimum values after 0.1 MGT of traffic.

NOTE: Typical values for a wood tie will range from a low of roughly 1,400 lbf at initial installation to roughly 3,500 lbf after 10 MGT of traffic. Because of the many variables that could affect the results of any given individual test, conclusive results are not possible by only performing a single test. If comparative results are desired, then the different types of ties must be installed in the same general vicinity and have been subjected to similar installation, traffic, ballast type, crib width, and ballast shoulder width.


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30Part 3

Solid Sawn Timber Ties

— 2015 —

FOREWORD

Section 3.1 through 3.5, Section 3.8 and Section 3.9 formulate specific and detailed rules for the design, handling, and inspection of wood cross ties and wood switch ties, and give data pertaining to their service life and economics. Section 3.6through Section 3.7 formulate specific detailed rules for the preservative treatment of wood cross ties, switch ties and other forest products, including specifications for preservatives.

TABLE OF CONTENTS


3.1 Timber Cross Ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-33.1.1 Specifications for Timber Cross Ties (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-33.1.2 Marking Ties to Indicate Size Acceptance (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-73.1.3 Explanations of Cross Tie Design (2013) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-83.1.4 Specifications for Machining Cross Ties (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-83.1.5 Specifications for Tie Plugs and Synthetic Tie Plugging Materials (2006) . . . . . . . . . . . . . . . . . . . . . 30-3-103.1.6 Specifications for Devices to Control the Splitting of Wood Ties (2012) . . . . . . . . . . . . . . . . . . . . . . 30-3-103.1.7 Application of Anti-Splitting Devices (2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-11

3.2 Timber Switch Ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-123.2.1 Specifications for Timber Switch Ties (2015) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-12

3.3 Tie Tests and the Economics of Service Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-153.3.1 Purpose of Tie Tests (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-153.3.2 Design (1975). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-153.3.3 Marking Test Ties (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-153.3.4 Economic Comparison of Service Life (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-173.3.5 Traffic Unit for Use in Comparing Tie Life (1975) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-18

3.4 Substitute Timber Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-183.4.1 Fundamentals to be Considered in Designs of Substitute Ties (2013) . . . . . . . . . . . . . . . . . . . . . . . . 30-3-18

3.5 The Handling of Ties from the Tree into the Track. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-203.5.1 Seasonal Manufacture (1975) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-20

Ties





3.5.2 Log Storage (1975). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-203.5.3 Specifications (1975) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-213.5.4 Inspection (2011) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-213.5.5 Transportation to the Treating Plants (2011) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-213.5.6 Seasoning (2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-213.5.7 Control of Splitting in Air Seasoning (1985) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-223.5.8 Machining (1985) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-253.5.9 Preservation (1985) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-253.5.10 Care After Preservative Treatment (2013) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-253.5.11 Distribution (2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-263.5.12 Care During and After Installation (2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-263.5.13 Renewals (2013). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-273.5.14 Salvage (1985) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-27

3.6 Wood Preserving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-293.6.1 Fundamentals (1985) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-293.6.2 Preparation of Material Prior to Treatment (2013) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-293.6.3 Conditioning Prior to Treatment (2013). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-303.6.4 Preservatives (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-323.6.5 Treating Plant Equipment (1985) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-353.6.6 Inspection of Treated Timber Products (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-353.6.7 Care of Material After Treatment (2013) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-353.6.8 Use of Treated Wood (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-353.6.9 Specified Requirements (2002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-36

3.7 Specifications for Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-363.7.1 General Requirements (2013). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-363.7.2 Treatment (2013) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-383.7.3 Results of Treatment (2013). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-403.7.4 Preservatives (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-403.7.5 Inspection (2013) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-413.7.6 Methods of Determining Penetration in Wood Treated with Preservatives (2002) . . . . . . . . . . . . . . 30-3-413.7.7 Retreatment (1995) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-423.7.8 Specific Requirements for Preservative Treatment by Pressure Process (2013) . . . . . . . . . . . . . . . . 30-3-42

3.8 Recommended Practice for the Manufacture of Two-Piece Steel Doweled Laminated Cross Ties (TPSDLC) 30-3-423.8.1 Material (1984). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-423.8.2 Design (2011) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-433.8.3 Inspection (1984) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-433.8.4 Delivery (1984) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-453.8.5 Shipment (1984) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-453.8.6 Tie Plates (1984). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-45

3.9 Specifications for Timber Industrial Grade Cross Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-463.9.1 Specifications (2015) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-46




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LIST OF FIGURES


30-3-1 Dimensions of 7-inch and 6-inch Cross Ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-530-3-2 Shake Allowances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-630-3-3 Clock Dating Tie Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-1630-3-4 Ties Stacked 20 Layers High, German Style, for Seasoning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-2330-3-5 End View of Stacks of Ties being Air-seasoned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-2430-3-6 Stickered Air-Dried Ties with Two Space Stickers Per Layer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-2430-3-7 Broad View of a Clean, Well Drained Air-dry Yard Seasoning Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-2530-3-8 Incising Pattern for Material Over Two Inches Thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-3030-3-9 Incising Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-3730-3-10 Determining the Length of Shake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-44

LIST OF TABLES


30-3-1 Species Groups for Seasoning and Treating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-2230-3-2 Requirements for Cross Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3-46

SECTION 3.1 TIMBER CROSS TIES1

3.1.1 SPECIFICATIONS FOR TIMBER CROSS TIES (2014)

NOTE: It is recommended for West Coast Species that West Coast Lumber Inspection Bureau (WCLIB) Grading Rules apply and for Southern Yellow Pine species that Southern Pine Inspection Bureau (SPIB) Grading Rules apply.

3.1.1.1 Material

3.1.1.1.1 Kinds of Wood2

Before manufacturing ties, producers shall ascertain which of the following kinds of wood suitable for Cross ties will be accepted:

1 References, Vol. 75, 1974, p. 379; Vol. 85, 1984, p. 7; Vol. 88, 1987, p. 55; Vol. 94, p. 61.2 Each railway will specify only the kind of wood it desires to use.

Ashes Elms Larches PoplarsBeech Firs (true) Locusts RedwoodsBirches Gums Maples SassafrasCatalpas Hackberries Mulberries SprucesCherries Hemlocks Oaks SycamoresDouglas fir Hickories Pines Walnuts

Ties



Others will not be accepted unless specially ordered.

3.1.1.1.2 Timber Ties of Non-Indigenous Species

a. Non-indigenous tie species must possess similar design characteristics to domestic species with regard to adequate rail bearing area, sufficient bearing surface on the ballast, maximum strength to prevent failure of the tie or the tie fastenings while providing against undue deflection in the rail. Tie size, along with the inclusion of all other indigenous wood tie specifications, mechanical properties, and quality must apply.

b. Regardless of the materials used and the quality of the construction, track will not remain permanently to gage, surface, and line under the loads imposed upon it in typical revenue service applications. Restorative and maintenance operations will, therefore, always be necessary. Some alternative tie species may provide additional resistance to any change in gage or line as may be caused by wheel loads and may allow for easy adjustment to correct any changes in track geometry that do occur. Density of the alternative species is the primary driver for this and thus evaluation of this property as well as specie workability is necessary.

c. All ties produced from non-indigenous species shall be manufactured in accordance with AREMA Chapter 30, Part 3, Solid Sawn Timber Ties, and shall be free of any defects that may impair their strength or durability for use as crossties, such as: decay, large splits, large shakes, slanting grain, or large or numerous holes or knots.

d. The decay resistance properties of heartwood and sapwood of non-indigenous wood species vary greatly. Both, the heartwood and sapwood, shall be tested in accordance with AWPA standards to determine the degree of natural decay resistance, which, in turn, determines if preservative treatment is necessary.

e. All alternative tie species must be tested to determine classification for resistance to termite infestation and fungal decay. Certain species may exhibit high resistance to decay and insect attack and determination of these properties by AWPA standard methodologies is recommended. “Highly Resistant” indicates the maximum resistance in this classification. If the species meets this classification, then preservative treatment is not necessary. Otherwise, treatment in accordance to AWPA Standards is recommended.

f. All alternative tie species must conform dimensionally in length, width, and thickness in a green and seasoned state, holding to the same standards for indigenous wood ties as outlined in Article 3.1.1.3.1.

g. Insulation – Ties produced from non-indigenous species must be tested to insure that they perform satisfactorily in regard to track circuitry, signaling and communication requirements.

h. Alternative tie species shall be tested to determine the suitability and application requirements of all plate and rail fastening hardware.

3.1.1.2 Physical Requirements

3.1.1.2.1 General Quality

Except as hereinafter provided, all ties shall be free from any defects that may impair their strength or durability as cross ties,such as decay, large splits, large shakes, slanting grain, or large or numerous holes or knots.

3.1.1.2.2 Resistance to Wear

When so ordered, ties from needled-leaved trees shall be of compact wood throughout the top fourth of the tie, where any inch of any radius from the pith shall have six or more rings of annual growth. Southern Yellow Pine ties shall conform to the mostcurrent SPIB Standard Grading Rules for Southern Pine Lumber; Section 400 - Timbers 5x5 or Larger - No. 1 Dense or better. West Coast Softwood species shall conform to the most current WCLIB Specifications - Standard No. 17 Grading Rules; Section 6: Special Use Grades - Railroad Ties; Item 192-b - No. 1 Railroad Ties or Better.




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3.1.1.3 Design

3.1.1.3.1 Dimensions

Ties shall be 8’-0", 8’-6", or 9’-0" long as specified by the customer. Thickness, width, and length specified are minimum dimensions for green ties. Dry or treated ties may be 1/4 inch thinner or narrower than the specified sizes. Ties exceeding thesedimensions by more than l inch shall be rejected. The grade of each tie shall be determined at the point of most wane on the topface of the tie within the rail-bearing areas. The rail-bearing areas are those sections between 20 inches and 40 inches from thecenter of the tie. The top of the tie shall be the narrowest face and/or the horizontal face farthest from the heart or pith center.

All rail-bearing areas shall measure as follows: 7-inch grade cross ties shall be 7" x 9" in cross section with a maximum of 1 inch of wane in the top rail-bearing areas. A maximum of 20% of the ties in any given quantity may be square-sawn 7" x 8" in cross section with no wane in the rail-bearing areas. A 6-inch grade tie shall be 6" x 8" in cross section with a maximum of 1 inch of wane permitted in the top rail-bearing areas. For both 6-inch and 7-inch grade ties, wane shall be permitted on the bottom face so long as it does not exceed 1 inch at any given point (Figure 30-3-1).

3.1.1.4 Inspection

3.1.1.4.1 Place

Ties shall be inspected at suitable points as specified in the purchase agreement of the railway.

3.1.1.4.2 Manner

Ties must be presented for inspection in an organized manner with all surfaces clean for ready observation. Inspectors will make a reasonably close examination of the top, bottom, sides and ends of each tie. Each tie will be judged independently, without regard to the decisions on others in the same lot.

3.1.1.4.3 Decay

Decay is the disintegration of the wood substance due to the action of wood destroying fungi. “Blue stain” is not decay and is permissible in any wood.

Figure 30-3-1. Dimensions of 7 -inch and 6 -inch Cross Ties

Ties



3.1.1.4.4 Holes

A large hole is one more than 1/2 inch in diameter and 3 inches deep within, or more than one-fourth the width of the surface on which it appears and 3 inches deep outside, the sections of the tie between 20 inches and 40 inches from its middle. Numerous holes are any number equalling a large hole in damaging effect. Such holes may be caused in manufacture or otherwise.

3.1.1.4.5 Knots

Within the rail bearing areas, a large knot is one having an average diameter more than 1/3 the width of the surface on which itappears; but such a knot will be allowed if it is located outside the rail bearing areas. Numerous knots are any number equalling a large knot in damaging effect.

3.1.1.4.6 Shake

a. A shake is a separation along the grain, most of which occurs between the rings of annual growth.

b. The procedure shown in Figure 30-3-2 shall be used to determine the length of a shake. One which is not more than one-third the width of the tie will be allowed, provided it does not extend nearer than l inch to any surface.

3.1.1.4.7 Split

A split is a separation of the wood extending from one surface to an opposite or adjacent surface. Do not count the end as a surface when measuring the length of a split. In unseasoned cross ties, a split no more than 1/8 inch wide and/or 4 inches long is acceptable. In a seasoned cross tie, a split no more than 1/4 inch wide and/or longer than the width of the face across whichit occurs is acceptable. In seasoned cross ties, a split exceeding the limit is acceptable, provided split limitations and anti-splitting devices are approved by the buyer and properly applied.

3.1.1.4.8 Checks

A check is a separation of the wood due to seasoning which appears on one surface only. Do not count the end as a surface. Ties with continuous checks whose depth in a fully seasoned and/or treated tie is greater than 1/4 the thickness and longer than1/2 the length of the tie will be rejected.

3.1.1.4.9 Slope of Grain

Except in woods with interlocking grain a slope in grain in excess of 1 in 15 will not be permitted.

Figure 30-3-2. Shake Allowances




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3.1.1.4.10 Bark Seams

A bark seam or pocket is a patch of bark partially or wholly enclosed in the wood. Bark seams will be allowed provided they are not more than 2 inches below the surface and/or 10 inches long.

3.1.1.4.11 Manufacturing Defects

All ties must be straight, square-sawn, cut square at the ends, have top and bottom parallel, and have bark entirely removed. Any ties which do not meet the following characteristics of good manufacture will be rejected:

a. A tie will be considered straight when a straight line from a point on one end to a corresponding point on the other end is no more than 1-1/2 inches from the surface at all points.

b. A tie is not well-sawn when its surfaces are cut into with scoremarks more than 1/2 inch deep, or when its surfaces are not even.

c. The top and bottom of a tie will be considered parallel if any difference at the sides or ends does not exceed 1/2, inch.

d. For proper seating of nail plates, tie ends must be flat, and will be considered square with a sloped end of up to 1/2 inch, which equals a 1 in 20 cant.

3.1.1.5 Delivery

3.1.1.5.1 On Railway Premises

Ties shall be delivered and stacked as specified in the purchase agreement of the railway. If ties are to be inspected, they mustbe placed so that all ties are accessible to the inspector.

3.1.1.5.2 Risk, Rejection

All ties are at the owner’s risk until accepted. All rejected ties shall be removed within one month after inspection.

3.1.1.6 Shipment

Ties forwarded in cars or vessels shall be separated therein according to the above groups, and also according to the above sizes if inspected before loading, or as may be stipulated in the contract or order for them.

3.1.2 MARKING TIES TO INDICATE SIZE ACCEPTANCE1 (2002)

3.1.2.1 General

Each tie shall be marked in accordance with the Railroad’s Specifications in such a manner that the marks will not be obliterated by treatment.

1 References, Vol. 31, 1930, pp. 1091, 1744; Vol. 53, 1952, pp. 336, 1120; Vol. 54, 1953, pp. 626, 1394; Vol. 61, 1960, pp. 407, 1167; Vol. 94, p. 62.

Ties



3.1.3 EXPLANATIONS OF CROSS TIE DESIGN1 (2013)

3.1.3.1 General

a. The size of ties most widely used under heavy mainline traffic has increased since 1905 from 6" x 8" x 8’ to 7" x 9" x 8’-6".

b. Owing to the many variables involved, including strength of timber in its average condition in track, condition of roadbed, etc., it is not possible to calculate a design for a tie in the sense that a bridge member is designed.

c. For heavy mainline traffic lines, ties meeting the standard specification for 7-inch grade ties should be used.

d. A space of 10 inches between tops of ties allows sufficient room for tamping; the maximum of bearing area on the ballast may be secured by the use of the wider and longer ties laid with this spacing.

e. Where ties shorter than 8’-6" are in use, in heavy mainline traffic lines, it is recommended that longer ties be used in the interest of promoting economy in track maintenance:

3.1.4 SPECIFICATIONS FOR MACHINING CROSS TIES2 (2014)

3.1.4.1 General

When ties are adzed, bored, branded, incised or trimmed, the operations required by any or all machining ordered shall be carried out before air-seasoning, or immediately prior to preserving, in accordance with the following specifications:

3.1.4.2 Adzing

Sawn ties provide a flat surface for tie plate seating which precludes the need for adzing.

3.1.4.3 Boring

a. Boring for spike holes is optional. If boring is done then boring for spike holes shall conform in size and location to plans provided, with ±1/16 inch permitted in each distance between holes. The spike holes shall be centered across the width of the tie in such a way that the tie plates will center on the tie when the spikes are driven into the prebored holes. A tolerance of 1/8 inch in the centering of the holes across the width of the tie is permissible.

b. The depth of the hole shall be bored in accordance to the individual customer specifications.

c. When the head diameter of the bits has been reduced 1/16 inch by wear, bits shall be replaced. Cutting heads of bits shall be sharpened at regular intervals to insure clean boring.

d. It is recommended:

(1) That 1/2 inch holes be bored in hardwood ties for 9/16 inch cut spikes.

(2) That 9/16 inch holes be bored in hardwood ties for 5/8 inch cut spikes.

(3) That 7/16 inch holes be bored in softwood ties for 9/16 inch cut spikes.

1 References, Vol. 25, 1924, pp. 128, 1221; Vol. 43, 1942, pp. 401, 696; Vol. 54, 1953, pp. 626, 1394; Vol. 63, 1962, pp. 316, 741; Vol. 85, 1984, p. 9; Vol. 94, p. 62.

2 References, Vol. 37, 1936, pp. 419, 989; Vol. 54, 1953, pp. 626, 1394; Vol. 62, 1961, pp. 409, 919; Vol. 67, 1966, pp. 176, 718; Vol. 85, 1984, p. 9; Vol. 94, p. 62.




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(4) That 1/2 inch holes be bored in softwood ties for 5/8 inch cut spikes.

3.1.4.4 Trimming

a. Trimmed ties shall be cleanly sawed at both ends to the specified length prior to treatment.

b. Machines shall be preferably equipped with devices for centering the ties lengthwise and where machines are so equipped equalizers and guides shall be so set that an equal amount is cut from each end of the tie. When machines are not equipped with equalizers, guides shall be set to trim 1/2 inch from one (line) end of tie and sufficient from the opposite end to result in the specified length.

3.1.4.5 Branding

a. Branding of ends or the top or bottom surfaces of the ties shall be done with letters, figures or symbols to indicate one or more of the following:

• Wood.

• Treatment(s).

• Weight of rail for which bored.

• Year manufactured or treated.

• Size.

• Identity of plant.

• Identity of railroad.

b. The height of letters and figures comprising the marking along with the specific location shall be determined by individual customer specifications.

(1) If ties are hydraulically machined or hammer branded on the ends, dies used shall have cutting edges 1/8 inch wide and shall indent the wood at least 1/4 inch deep.

(2) Burn branding is also allowed and must produce burn identification marks that penetrate at least 1/8" wide and at least 1/8" deep.

(3) If ties are to be end-plated, it is preferred to have end-plates embossed with the marking in the webbing in at least one location on the plate.

(4) Date-nailing is also an acceptable method of identification. Nails must be ring shank type galvanized steel or aluminum with embossed head. Nails must be driven flush to the surface or end of the tie.

Ties



3.1.5 SPECIFICATIONS FOR TIE PLUGS AND SYNTHETIC TIE PLUGGING MATERIALS1

(2006)

3.1.5.1 General Background

Wood tie plugs and synthetic tie plugging materials are used to fill holes left in ties after plate and rail fasteners, such as cut spikes and screw spikes, are removed.

3.1.5.2 Purpose

Tie plug and synthetic tie plugging materials serve two primary purposes.

a. To protect the tie from environmental contamination.

b. To provide new material into which fasteners may be re-installed.

3.1.5.3 General Quality

a. For maximum effectiveness, wooden plugs must fit tightly in the vacated holes. The dimensions and preservative treatment of wooden plugs may be recommended by the tie plug manufacturer or specified by the end user.

b. For maximum effectiveness, synthetic plugging materials must completely fill the vacated holes. Cure time and material hardness may be recommended by the manufacturer of the plugging material or specified by the end user.

3.1.6 SPECIFICATIONS FOR DEVICES TO CONTROL THE SPLITTING OF WOOD TIES2

(2012)

3.1.6.1 Anti-Splitting Devices

Anti-splitting devices may be of (a) the type made from a strip of steel and applied by driving into the end (cross section) ofthe tie; or (b) of the steel dowel type, applied parallel to the wide face of the tie, transverse to its length; or (c) the steel multi-nail plate type to be pressed or driven flush into the end (cross section) of the tie.

3.1.6.2 Materials

3.1.6.2.1 Dowels

If the steel dowel type is used, it shall be of the dimensions and thread design specified by the purchaser, and shall be of C-1020 steel, ASTM Specifications, designation A 575-96 (2002), with a minimum of 0.2 of 1% copper.

3.1.6.2.2 Irons

a. The finished strip shall conform to the following minimum tensile properties:

b. Design. Anti-splitting irons shall be of the shape and size stipulated by the purchaser.

1 References, Vol. 26, 1925, pp. 1079, 1433; Vol. 54, 1953, pp. 627, 1394; Vol. 61, 1960, pp. 407, 1167.2 References, Vol. 32, 1931, pp. 236, 736; Vol. 45, 1944, pp. 270, 598, Vol. 63, 1962, pp. 316, 741; Vol. 85, 1984, p. 9.

Strength, psi . . . . . . . . . . . . . . . . . 75,000Yield point, psi . . . . . . . . . . . . . . . 40,000Elongation in 2 in., percent . . . . . 20




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c. Manufacture. Anti-splitting irons shall have smooth surfaces and be free of distortion, scale, jagged ends, and blunt beveled edge.

The dimensions of the steel strip in anti-splitting irons shall be not less than:

d. Variations. Variations (over or under) from dimensions specified shall not exceed:

3.1.6.2.3 Nail Plates

If a steel nail plate is used it shall be made of 18 gage galvanized sheet steel ASTM A653/A653M Structural Steel (SS) Grade 40 or better with a minimum coating designation of G60. ASTM A653/A653M SS Grade 40 G60 mechanical properties are as follows:

Yield Strength - 40,000 psi minimum

Ultimate Tensile Strength - 55,000 psi minimum

Elongation in 2 inches - 16% minimum

3.1.6.3 Inspection

Inspectors representing the purchaser shall have free entry, at all times while work on the contract of the purchaser is being performed, to all parts of the manufacturer’s works which concern the manufacture of the material ordered. The manufacturer shall afford the inspectors, without charge, all reasonable facilities to satisfy them that the material is being supplied in accordance with these specifications. Unless otherwise agreed all inspection and tests shall be made at the place of manufacture prior to shipment, and shall be so conducted as to not interfere unnecessarily with the operation of the works.

3.1.6.4 Delivery

Accepted devices shall be shipped by the seller in accordance with instructions in the order covering them, securely packed in containers marked with the name, type, grade, and quantity of the material therein, and with the name of the seller and the number of the buyer’s contract or order.

3.1.7 APPLICATION OF ANTI-SPLITTING DEVICES1 (2005)

3.1.7.1 General

a. All hardwood ties (those from broadleaved trees) are subject to splitting and when so designated by the purchaser shall have anti-splitting devices applied. Either nail plates, strip irons or dowels may be used for this purpose.

Thickness . . . . . 0.083 in.Width . . . . . . . . 3/4 in.Length . . . . . . . as required by the design

Thickness . . . . . . . . . . 0.005 in.Width of strip . . . . . . . 1/32 in.Width of bevel . . . . . . 1/32 in.Length . . . . . . . . . . . . 1/8 in.

1 References, Vol. 32, 1931, pp. 236, 736; Vol. 45, 1944, pp. 270, 598; Vol. 63, 1962, pp. 318, 741; Vol. 85, 1984, p. 9.

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b. Anti-splitting devices designed to control the splitting of ties should be applied prior to or at the time the ties are delivered to the treating plant.

3.1.7.2 Nail Plates

a. One multi-nail plate should be positioned onto the end (cross section) of the tie, with the plate being placed to cover the greatest area of splitting. This should enable the plate to hold both vertical and horizontal splits together.

b. Nail plates should be applied by a mechanical device capable of squeezing the splits together, bringing the tie back to its original dimensions, prior to application.

3.1.7.3 Irons

Anti-splitting strip irons driven into the ends of ties should be so placed as to cross at right angles the greatest possible mannerof radial lines of the wood. Irons should be placed far enough from the wide faces to prevent splitting.

SECTION 3.2 TIMBER SWITCH TIES1

3.2.1 SPECIFICATIONS FOR TIMBER SWITCH TIES (2015)

NOTE: It is recommended for West Coast species that West Coast Lumber Inspection Bureau (WCLB) Grading Rules apply.

3.2.1.1 Material

3.2.1.1.1 Kinds of Wood

a. Before manufacturing ties, producers shall ascertain which of the following kinds of wood suitable for switch ties will be accepted:

b. Others will not be accepted unless specially ordered.

3.2.1.2 Physical Requirements

3.2.1.2.1 General Quality

Except as hereinafter provided, all ties shall be free from any defects that may impair their strength or durability as switch ties,such as decay, large splits, large shakes, slanting grain, or large or numerous holes or knots.

1 References, Vol. 17, 1916, pp. 245, 840; Vol. 22, 1921, pp. 332, 1005; Vol. 27, 1926, pp. 695, 1388; Vol. 35, 1934, pp. 780, 1160; Vol. 53, 1952, pp. 336, 1120; Vol. 54, 1953, pp. 626, 1394; Vol. 55, 1954, pp. 470, 1074; Vol. 63, 1962, pp. 318, 741; Vol. 75, 1974, p. 379; Vol. 88, 1987, p. 55; Vol. 94, p. 63.

Ashes Elms Larches RedwoodBeech Firs (true) Locusts SprucesBirches Gums Maples WalnutsCherries Hemlocks OaksDouglas fir Hickories Pines




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3.2.1.2.2 Resistance to Wear

When so ordered, ties from needle-leaved trees shall be of compact wood throughout the top fourth of the tie where any inch of any radius from the pith shall have 6 or more rings of annual growth. Southern Yellow Pine ties shall conform to the most current SPIB Standard Grading Rules for Southern Pine Lumber; Section 400 – Timbers 5x5 or Larger – No. 1 Dense or Better. West Coast Softwood species shall conform to the most current WCLIB Specifications – Standard No. 17 Grading Rules; Section 6: Special Use Grades – Railroad Ties; Item No. 192-b – No. 1 Railroad Ties or Better.

3.2.1.3 Design


a. All unseasoned or green switch ties shall measure in cross section a minimum of 7 inches in side thickness and 9 inches in face width. A maximum of 1 inch of wane is allowed on the top or bottom faces within the rail-bearing area, which is defined as the section between 12 inches from each end of the tie. Seasoned or treated switch ties may be 1/4 inch under the specified dimensions for thickness and width, or not more than 1 inch over the specified dimensions. Lengths and length tolerances shall be specified by the customer.

b. All thickness and face width dimensions apply to the rail-bearing area. All determinations of face width shall be made on the top of the switch tie, which is the narrowest horizontal face. If both horizontal faces are of equal width, the top shall be that face with the narrowest or no heartwood.

3.2.1.4 Inspection

3.2.1.4.1 Place

Ties shall be inspected at suitable points as specified in the purchase agreement of the railway.

3.2.1.4.2 Manner

Ties must be presented for inspection in an organized manner with all surfaces clean for ready observation. Inspectors will make a reasonably close examination of the top, bottom, sides and ends of each tie. Each tie will be judged independently without regard to the decisions on others in the same lot.

3.2.1.4.3 Decay

Decay is the disintegration of the wood substance due to the action of wood destroying fungi. “Blue stain” is not decay and is permissible in any wood.

3.2.1.4.4 Holes

A large hole is one more than 1/2 inch in diameter and 3 inches deep within, or more than one-fourth the width of the surface on which it appears and 3 inches deep outside, the section of the tie between 12 inches from each end of the tie. Numerous holes are any number equaling a large hole in damaging effect. Such holes may be caused in manufacture or otherwise.

3.2.1.4.5 Knots

Within the rail bearing area of switch ties, which is that area between 12 inches from each end of the tie, a large knot is onehaving an average diameter more than 1/3 the width of the surface on which it appears, but such a knot may be allowed if it is located outside the rail bearing area. Numerous knots are any number equaling a large knot in damaging effect.

3.2.1.4.6 Shake

a. A shake is a separation along the grain most of which occurs between the rings of annual growth.

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b. The procedure shown in Article 3.1.1.4.6 and Figure 30-3-2 for crossties shall also apply to switch ties for measuring the length of a shake. One which is not more than one-third the width of the tie will be allowed provided it does not extend nearer than 1 inch to any surface.

3.2.1.4.7 Splits

a. A split is a separation of the wood extending from one surface to an opposite or adjacent surface. Do not count the end as a surface when measuring the length of a split.

b. In unseasoned or green switch ties, a split no more than 1/8 inch wide and/or 5 inches long is acceptable. In a seasoned or treated switch tie, a split no more than 1/4 inch wide and/or longer than the width of the face across which it occurs is acceptable. A split exceeding the limit is acceptable, provided split limitations and anti-splitting devices are approved by the buyer and properly applied.

3.2.1.4.8 Checks

A check is a separation of the wood due to seasoning which appears on one surface only. Do not count the end as a surface when measuring the length of a check. Ties with continuous checks whose depth in a fully seasoned and/or treated tie is greater than 1/4 the thickness and longer than 1/2 the length of the tie will be rejected.

3.2.1.4.9 Slope of Grain

Except in woods with interlocking grain, a slope of grain in excess of 1 in 15 will not be permitted.


A bark seam or pocket is a patch of bark partially or wholly enclosed in the wood. Bark seams will be allowed provided they are not more than 2 inches below the surface and/or 10 inches long.


All ties must be straight, square-sawn, cut square at the ends, have top and bottom parallel, and have bark entirely removed. Any ties which do not meet the following characteristics of good manufacture will be rejected:

a. A tie will be considered straight when a straight line from a point on one end to a corresponding point on the other end is no more than 2 inches from the surface at all points.

b. A tie is not well-sawn when its surfaces are cut into with scoremarks more than 1/2 inch deep, or when its surfaces are not even.

c. The top and bottom of a switch tie will be considered parallel if any difference at the sides or ends does not exceed 1/2 inch.

d. For proper seating of nail plates, tie ends must be flat, and will be considered square with a sloped end of up to 1/2 inch, which equals a 1 in 20 cant.

3.2.1.5 Delivery






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All ties are at the owner’s risk until accepted. All rejected ties shall be removed within one month after inspection.

3.2.1.6 Shipment

Ties forwarded in cars or vessels shall be separated therein according to the above groups, and also according to the above setsor lengths if inspected before loading, or as may be stipulated in the contract or order for them.

SECTION 3.3 TIE TESTS AND THE ECONOMICS OF SERVICE LIFE1

3.3.1 PURPOSE OF TIE TESTS (2014)

a. Tie tests may be installed to demonstrate average years of service life under various conditions, sizes, designs, materials, spacing, wood species, preservatives, retentions, tonnage, anti-splitting devices, coatings, grade, curvature, speed, rail size, etc.

b. For the purpose of evaluating new railroad tie products, consider published references such as the Railway Tie Association’s document "Gateway Document for Candidate Railroad Tie Products".

3.3.2 DESIGN2 (1975)

a. Test sections shall be so devised that all of the variables affecting life, except the one to be determined, will, as far as possible, neutralize or cancel out.

b. Thus, if the effect of size is to be determined, the test should be designed as follows:

(1) Select a location where the various sizes to be tested are inserted under one tangent track with constant grade, drainage, and ballast.

(2) Use ties of the same species of wood, treated with one preservative to the same retention.

(3) Use identical fastenings, plates and anti-splitting devices.

c. If the effect of traffic is to be determined, a location should be chosen where adjacent tangent tracks are similar in all respects except for tonnage.

3.3.3 MARKING TEST TIES3 (2014)

a. Test ties must be physically identified for the life of the test. Some of the acceptable means include:

(1) dating nails,

(2) surface and/or end markings,

(3) tags of metal or other materials suitable to withstand weathering and tie tests,

(4) shallow bore holes,

1 References, Vol. 75, 1974, p.3792 References, Vol. 24, 1923, pp. 256, 1148; Vol. 28, 1927, pp. 189, 1288; Vol. 54, 1953, pp. 627, 1394; Vol. 63, 1962, pp. 319, 741.3 References, Vol. 27, 1926, pp. 702, 1388; Vol. 48, 1947, pp. 377, 875; Vol. 54, 1953, pp. 627, 1394; Vol. 63, 1962, pp. 319, 741; Vol. 67, 1966, pp. 176, 718.

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(5) paint

(6) embossed nail plates.

(7) branding

(8) electronic identification

Methods (1), (3) and (4) are usually located 10 inches toward the tie center from the inside edge of the tie plate on the line side.

b. It is recommended that all ties be physically identfied to indicate one or more of the following: the year of purchase or treatment, wood species group, kind of treatment, and treating plant identification.

c. One former method of dating ties is called Clock Dating. For reference, this method is described and illustrated in Figure 30-3-3.

Figure 30-3-3. Clock Dating Tie Method




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3.3.4 ECONOMIC COMPARISON OF SERVICE LIFE1 (2014)

a. Except in isolated cases, ultimate economy in labor and material results from the use of properly treated ties, as compared with untreated ties.

b. The economy of any tie of known price and life may be determined by the following formulas:

• Required – Total capitalization of tie:

where:

• Required – Total annual cost:

• Total annual cost =

where:

• Tie costs are equivalent when the capitalization or annual costs are equal, or:

1 References, Vol. 16, 1915, pp. 524, 1091; Vol. 40, 1939, pp. 635, 786; Vol. 53, 1952, pp. 337, 1120; Vol. 54, 1953, pp. 626, 1394; Vol. 55, 1954, pp. 470, 1074; Vol. 63, 1962, pp. 319, 741.

C = First cost of tie

C1= Amount of money at compound interest which will produce interest equaling first cost of tie, during life of tie

R = Rate of interestn = Life of tie in years

C = First cost of tie R = Rate of interest I = Interest on first cost

A = Amount of money at compound interest which will provide for renewal at end of life of tien = Life of tie in years

C C1 C 1 R+ n

1 R+ n 1–-----------------------------=+

I CR=

A CR

1 R+ n 1–-----------------------------=

I A+ CR 1 R+ n

1 R+ n 1–-----------------------------=

C2 C 1 R+ n

1 R+ n 1–----------------------------- 1 R+ n1 1–

1 R+ n1--------------------------------=

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where:

c. Other tie life cycle costing models are available from sources such as:

(1) Railway Tie Association

(2) Treated Wood Council

3.3.5 TRAFFIC UNIT FOR USE IN COMPARING TIE LIFE1 (1975)

For comparing cross tie service, the density of traffic units shall be the “Equivalent gross ton-miles per mile of track,” determined according to the formula given below:

Let:

NOTE: The term 144 P embraces passenger locomotives.

SECTION 3.4 SUBSTITUTE TIMBER TIES2

3.4.1 FUNDAMENTALS TO BE CONSIDERED IN DESIGNS OF SUBSTITUTE TIES (2013)

3.4.1.1 General

a. The substitute must be designed to have sufficient strength to prevent failure of the tie or its fastenings, and sufficient bearing surface on the ballast and with the rail to properly support the loads imposed, and provide against undue deflection in the rail.

b. Track will not remain permanently to gage, surface and line under the loads imposed upon it, and restorative or maintenance operations, more or less frequent, will always be necessary. Therefore, the tie design should provide a maximum resistance to any change in gage or line as may be caused by wheel loads and should allow easy adjustment to correct for any change in track gage.

R = Rate of interestC = Cost of tie of n years life

C2 = Cost of tie of n1 years life

1 References, Vol. 31, 1930, pp. 1144, 1747; Vol. 49, 1948, pp. 238, 601; Vol. 54, 1953, pp. 627, 1394; Vol. 63, 1962, pp. 319, 741.

D = Equivalent gross ton-miles per mile of maintained trackN = Net ton-miles, freightT = Ton-miles, freight cars (tare)L = Ton-miles, freight locomotivesP = Passenger car miles

M = Miles of maintained trackD =

2 References, Vol. 24, 1923, pp. 249, 1147; Vol. 54, 1953, pp. 627, 1394; Vol. 63, 1962, pp. 319, 741; Vol. 75, 1974, p. 379.

N T 2L 144P+ + +

M----------------------------------------------




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c. The life cycle per unit of length of track for renewals and track maintenance should compare favorably with wood ties. Economy in renewals depends upon first cost, ease of installation and durability. Economy in maintenance will depend upon how closely the requirements heretofore specified are met.

3.4.1.2 Fastenings and Gage

a. The fastenings must be of sufficient strength to maintain gage and resist rail creepage, being so designed that without taking the tie from the track and without change to the holes, or fixed bolts or projections in the tie, a reasonable change of width or thickness of the base of rail, or variation of gage, may be made. The fastenings should be such as to offer as little obstruction to derailed wheels as possible. They should permit shimming where necessary, the change of defective rail, or the renewal of rails with ease, and should be replaceable if broken or defective, without disturbing the tie.

b. The combination of rail bearing area and lateral fastening restraint must be sufficient to withstand expected lateral loads without excessive gage widening due to canting of rail.

c. If the design provides one support under each rail, united by a transverse member to hold gage, the transverse member must be of sufficient strength to maintain gage and plane, and of such design as to withstand a reasonable amount of the damage incident to derailment.

3.4.1.3 Line

The tie should be of such shape that it will not only resist the tendency of track to get out of line, but also permit the track to be thrown back to line when necessary. Projections of the base of the tie that project into the ballast make it necessary to lift thetrack out of surface before relining, and are therefore objectionable. Ties clamped in pairs which enclose a considerable amount of ballast between their several parts, to such extent that the ballast must be removed before the track is lined, add amaterial burden to the labor necessary to line track.

3.4.1.4 Surface

a. The tie should have sufficient length and breadth to provide a bearing surface per rail length of track at least equal to that obtained with wood ties, for the same class of track, without reducing the space between the ties to such an extent as to make tamping difficult. It should have sufficient stiffness as a beam to develop the full bearing area on the roadbed.

b. The base of the tie must be so shaped that the ballast can be readily and effectively tamped under the tie and also not cut into or disturb the tamped bed.

3.4.1.5 Insulation

Ties to be used in track circuit territory should be insulated if their native impedance or resistance is insufficient to ensureproper operation of electrical devices. The fastenings of such ties should be so designed that the insulation material will not be subjected to abrasion or to great stress other than compression.

3.4.1.6 Causes of Failure

Past experience indicates that some of the features that produce failure in substitute ties are as follows:

a. Lack of efficient protection against corrosion.

b. Failure of rail fastenings.

c. Failure of insulation.

d. Loss of beam strength due to weakening tie in vicinity of rail or tie center, resulting in flexure cracking.

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e. Use of sharp interior angles, square holes, or other stress risers from which cracks develop.

f. Lack of resistance to derailed wheels.

g. Design of base of tie such as to render tamping difficult or impossible and such as to make maintenance of proper surface of track impracticable.

h. Design of tie such that track will not hold line, or such as to make lining of track impracticable.

i. Lack of beam strength causing breakage on yielding roadbed.

j. Lack of protection from abrasion by ballast.

k. Lack of provision for expansion and contraction, where materials with varying coefficients of expansion are used in combination.

l. Lack of compressive strength or ability to resist crushing action of tie plate or rail.

m. Lack of lateral strength, causing loss of retentive power of spikes, bolts, or other similar devices and insufficient resistance to their lateral thrust.

SECTION 3.5 THE HANDLING OF TIES FROM THE TREE INTO THE TRACK1

Long, satisfactory tie life stems from adherence to proven production practices beginning in the woods.

3.5.1 SEASONAL MANUFACTURE (1975)

Investigations of the moisture content of standing trees prove that during winter they contain as much sap as during other seasons. Consequently, felling timber during spring or summer does not result in ties having more moisture than would otherwise be the case. However, winter cutting is advantageous to the extent that then the cut surfaces of logs and ties are exposed first during cold weather, when fungi and insects are least active. By the time warm weather comes, winter-cut forest products are usually out of the woods (where destructive agents are the most prevalent) and become partly seasoned, decreasing the tendency for fungi to develop and reducing the liability to insect attack. It is also true that ties dry more slowlyduring the winter and early spring than they do in the summer, thereby reducing the tendency to excessively split and check. Because winter cutting is not everywhere practicable, owing to climatic or other conditions, it is necessary in most sections ofthe country that ties be manufactured throughout the year. Entirely satisfactory ties can be produced during any season if proper precautions are observed.

3.5.2 LOG STORAGE (1975)

Soil generally contains many species of fungi and is usually moist enough to dampen any wood in contact with it, thus providing the source of infection and conditions conducive to its propagation. Consequently, tie-logs should be moved as promptly as possible from woods to mill. Where prime seasons must be used for log hauling, pre-cut logs should be carefully stacked above the ground.

1 References, Vol. 24, 1923, pp. 251, 1148; Vol. 32, 1931, pp. 260, 740: Vol. 37, 1936, pp. 417, 989; Vol. 46, 1945, pp. 470, 812; Vol. 54, 1953, pp. 626, 1394; Vol. 63, 1962, pp. 319, 741; Vol. 67, 1966, pp. 177, 718; Vol. 68, 1967, p. 182; Vol. 75, 1974, p. 379; Vol. 86, 1985, p. 9.




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3.5.3 SPECIFICATIONS (1975)

Ties manufactured and purchased in accordance with AREMA specifications will meet requirements as to quality and size which assure the greatest economy in wood utilization and maximum service in track.

3.5.4 INSPECTION (2011)

a. If ties are to be inspected from solid stacks at mills or concentration yards prior to shipment, the inspection should take place as promptly as possible after being sawn to prevent stain and fungi build-up. If, for some reason, ties must be held for more than four winter months or one summer month, they should be air stacked in accordance with Article 3.5.6.2.

b. To reduce the high cost of mill or concentration yard inspection due to unavoidable delays, ties may be inspected at unloading stations located at destination treating plants or other tie inspection facilities. The area designated for inspection should be equipped with a kicker for turning, a mirror for observing the ends of ties opposite the inspection station, proper lighting and equipment for mechanical handling and separating.

c. Accepted ties should be marked to show ownership, year produced, and other information as specified.

3.5.5 TRANSPORTATION TO THE TREATING PLANTS (2011)

It may be advantageous to make provisions for the assignment of a sufficient number of cars or trucks to promptly handle the movement of green ties from concentration and/or mill yards to the tie inspection facility for seasoning prior to treatment. Delays in loading and hauling “dead” stacked ties may result in wood fiber infection.

3.5.6 SEASONING (2005)

3.5.6.1 Methods

Methods of seasoning should include air drying, Boultonizing, Steam Conditioning or other approved process.

3.5.6.2 Air Seasoning

a. Ties should be yarded in accordance with provisions set down under AREMA Plant Practice,Article 3.6.3.

b. Because the various species and sizes of ties dry at different rates, it is necessary to stack like kinds together-thus, No. 4 and No. 5 oaks would be stacked by themselves as would No. 3 beech, birch and maple. Hickory, pine and red gum are often stacked as separate species due to peculiar seasoning characteristics.

c. Tie stacks should contain only those ties received during the same month or 30 day period and be so labeled. This practice will bring ties out of air seasoning prior to treatment at the approximately same moisture content, preventing over- or under-drying.

d. Ties should be stacked for air seasoning in a manner which will allow free circulation of air, minimum contact of surfaces, maximum rain run off and maximum economy of space consistent with economical handling. It is recommended that stacks be built not over 20 layers high and the ties arranged 1 × 7 to 9. (Figure 30-3-4, Figure 30-3-5, Figure 30-3-6 and Figure 30-3-7.)

e. Ground contact sills should be of sound treated wood or of inorganic materials.

f. In areas where ties are subject to excessive splitting and checking during air seasoning, semi-solid square stacks (7 to 9 × 7 to 9) with end ties turned on their edges may be employed.

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g. Other methods of reducing air seasoning defects which have been successfully demonstrated are stacking ties under the roof of a pole shed, covering open stacks with portable pile covers, tie end-coating and incising.

3.5.6.2.1 Species Groups for Seasoning and Treating

Crossties shall be grouped as shown in Table 30-3-1 for air-seasoning or artificial seasoning and subsequent preservative treatment. Only the kinds of wood named in a group may be processed together.

3.5.7 CONTROL OF SPLITTING IN AIR SEASONING (1985)

a. Wooden ties, in particular the hardwood species, check and split under fast or prolonged drying due to differential shrinkage.

b. Hardwood ties may be protected prior to or during seasoning by the application of one or more of the anti-splitting devices, at or near both ends, as outlined in Article 3.1.6.1.

c. Splitting and/or excessive checking can be retarded in air seasoning by sheltering, arranging tie stacks so that tie ends do not face prevailing winds, turning the heart faces of top ties down, incising and end coating.

d. Ties can be originally incised, and then only those ties developing a definite split at the close of the air seasoning period are selected for application of split control devices.

Table 30-3-1. Species Groups for Seasoning and Treating

Group Ta Group Tb Group Tc Group TdBlack LocustHoney LocustRed OaksWhite OaksBlack Walnut

Douglas FirFirs (True)HemlocksLarchesPinesRedwoodSpruces

Gums AshesBeechBirchesCherriesElmsHard MaplesHickorySoft MaplesWhite Walnut




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Figure 30-3-4. Ties Stacked 20 Layers High, German Style, for Seasoning

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Figure 30-3-5. End View of Stacks of Ties being Air-seasoned

Figure 30-3-6. Stickered Air-Dried Ties with Two Space Stickers Per Layer




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3.5.8 MACHINING (1985)

a. Ties may be bored prior to treatment to minimize splitting when driving spikes and provide preservative penetration around the spike holes.

b. Incising is recommended prior to seasoning to hasten seasoning, retard splitting and serious checking and permit deeper preservative penetration of recalcitrant woods.

c. Poorly sawn ties should be adzed prior to seasoning or treatment for the purpose of insuring even support for tie plates in the same plane.

3.5.9 PRESERVATION (1985)

a. When long service life is desired, ties should be subjected to preservative treatment to insure against early failure from both fungi and insects.

b. To determine the most economical treatment requires careful and complete study of the species of woods available, preservatives available, conditions of use and results of previous tie tests.

c. The preservative treatment of ties should be in accordance with Section 3.6, Wood Preserving.

3.5.10 CARE AFTER PRESERVATIVE TREATMENT (2013)

a. Ties treated in excess of those needed at the time on line should be stored at the treating plant until required in order to provide better care and a more flexible supply than is practicable when surplus ties are stored along the right-of-way.

b. It is recommended that treated ties be stored as steel-strapped or wired tram bundles. Stacks of bundles should be stored on treated sills and should be separated with treated strips for efficient lift truck or crane rehandling.

c. It is important that treated ties be handled carefully and in such a manner that the protective sheath of preservative-treated fibers will not be broken, thereby exposing untreated heartwood to infection and insect attack. An incision made by a pick or fibers broken by the mis-blow of a maul may provide an opening through which decay may enter.

Figure 30-3-7. Broad View of a Clean, Well Drained Air-dry Yard Seasoning Ties

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3.5.11 DISTRIBUTION (2005)

a. Conditions affecting the distribution of ties in various localities differ so greatly that it is impractical to single out anyprocedure as universally superior. Careful study by all departments concerned is required to determine the best method of moving ties from each point of storage.

b. As a rule, it is more economical to load ties to cars directly from treatment, thereby saving one handling. Although direct loading is highly desirable, seasoning schedules may often require the storage of treated ties and rehandling will be necessary.

c. Tram bundles of treated ties are usually crane loaded, crosswise, into a gondola car. Each tie is then unloaded to a point along the right-of-way opposite the tie to be replaced.

d. Ties will be shipped from treating plants for usage under three general conditions:

(1) A large number of ties for renewal in connection with mechanized maintenance work over a several consecutive mile work location. These ties are best handled in special tie cars designed for this purpose, facilitating rapid unloading with minimum maintenance labor and greater safety. Ties should be unloaded at the point of usage to avoid labor expense in stacking or rehandling. Time between unloading and insertion should be the minimum practical to avoid damage to ties due to exposure to elements.

(2) A small number of ties to separate locations for use as on-line emergency stock or spot renewals. Handling can be in special tie cars or in such other cars as the railroad has available.

(3) A large number of ties shipped for use in construction work. The loading and handling method should mesh with the construction situation. Banded bundles can be used if ties are to be transferred from railway cars to trucks. Special tie cars are practical for adjoining track construction.

e. Ties should be carefully handled in a manner which will prevent breaking or bruising. Ties should not be discharged from cars onto rails or rocks. If a tie pick is used, it should be inserted in the end only.

f. Treated ties not needed for immediate use should be solidly stacked and may be covered with cinders or earth for protection against weather.

3.5.12 CARE DURING AND AFTER INSTALLATION (2005)

a. Ties should be carefully handled from the right-of-way to the point of insertion, guarding the vulnerable treated exterior.

b. Ties should be protected from excessive abrasion under the rail by the application of tie plates of sufficient area and thickness to distribute the traffic loads adequately. The least damage to ties as well as the smoothest track result from the use of plates having bottoms which do not necessitate the impact of traffic to seat the plate.

c. In order to economically enjoy the longest and most satisfactory service life from treated wooden ties, highest standards of surface and sub-surface maintenance must be practiced.

d. Ties should be adzed only in cases of necessity, as when rail is relaid, plate size changed or when the damage from a derailment involves the removal of splinters and crushed wood fibers. Whenever deep adzing of the treated surface takes place, steps should be taken to protect the adzed surfaces with a penetrating preservative paste or a preservative treated pad. Some states may require the applicator supervisor to have a permit for handling of pesticides.

e. Used spike holes should be filled with treated plugs or by chemical means.

f. Damage to ties from slewing as a result of rail creeping or running should be prevented by adequate anchoring of the rail.




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g. Ties of the species and size best suited for each location should be selected. Ties made from the denser hardwoods should be used in sharp curves, steep grades, at ends of open-deck bridges and where tonnage is excessively heavy.

h. Treated ties should be placed in track with the wide surface nearest the pith, down.

i. Ties should be laid square across the track; i.e. at right angles to the rail.

j. Care should be taken to set and drive spikes at right angles to the tie surface, straight down.

3.5.13 RENEWALS (2013)

a. Although differences in operational organizations and physical conditions on the various railroads make it impractical to formulate a procedure that is applicable everywhere, no phase of track maintenance is more important than the selection of the ties to be renewed in a given year. Improper tie renewals over a period of years are sure to be costly, and may prove to be disastrous, whether the replacements are too few or too many.

b. The total number of ties required to maintain satisfactory track in one year is rarely the same as the number renewed during the previous year or the average renewals over any period. Therefore, careful inspection of the ties in track will provide more dependable information than any assumptions based on statistics.

c. Whatever method is used in the inspection and selection of the ties to be renewed, the procedure should be so planned as to provide a record of the system requirements as distinguished from those of a section or division. Training and experience for those making inspections of ties in track are necessary to assure uniformity in their procedure and consistency in their conclusions.

d. Each tie to be removed is generally identified by a mark on the tie or on the rail above it. Absolute adherence to this marking is required in some instances. More often the foreman is allowed to leave some marked ties and to remove some unmarked ties. Ordinarily, only ties which are useless where they are should be removed; but when track is given a general out-of-face overhauling, all ties which appear to be nearing the end of their service life may be removed.

e. Records of inspections of ties in track, detailed as to location by subdivision, track, milepost, and/or GPS coordinates aid in the unloading of ties where needed and thus avoid expensive extra handling.

3.5.14 SALVAGE (1985)

a. Ties still serviceable enough for economical reuse become available when lines are abandoned and tracks are taken up; when the renewal of all ties in tunnels, in road crossings, or at station platforms releases them; and when ties under heavy traffic have to be removed because their service in such track is no longer satisfactory.

b. While the reclamation or salvage of ties is sound in principle and highly desirable, it can easily be overdone. To guard against any tendency toward false economy resulting from loyalty to reclamation as such, all costs must be considered. Complete records of all expenses connected with picking up, stacking, preparing, and shipping ties for reuse should be kept for comparison with the prices of other materials for a given purpose, together with the respective costs of installation. Expenditures for handling and hauling may confine their reuse to locations close to where they are removed from track.

c. The most economical use of ties is to leave them in their original locations until they are so decayed or mechanically worn that they cannot serve their purposes any longer. However, in connection with general track reconditioning, it is usually economical to replace ties near the end of their serviceability, in order that the track need not be disturbed again for several years. This procedure is desirable in heavy-traffic, high-speed lines where spot tie renewals are expensive and the disturbance of refined track surface is especially inadvisable.

d. Ties removed from track should be carefully inspected and sorted into those fit for reuse in tracks, those suitable for other uses and “culls.”

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e. Generally, secondhand usable ties have had their original quality lowered, and in consequence their reuse should be confined to tracks of lesser importance, such as those in light-traffic branch lines, sidings and yards. These ties should be reinserted in track quickly to avoid accelerated deterioration.

f. Ties reusable in track should be re-inserted with the same surface up as in original location. Only when light adzing of that surface will not provide satisfactory seats for the tie plates should ties be turned over.

g. All spike holes in reused ties should be filled with tight-fitting treated plugs.

h. Treated tie plugs can be inserted and a preservative paste or a preservative treated pad applied to the plate bearing areas advantageously as the removal of the rail progresses during the recovery of serviceable ties.

i. The following are visual characteristics a tie should possess to be considered salvageable:

(1) Rail seats sound, no evidence of decay.

(2) Limited mechanical wear under the tie plates.

(3) Spike holes sound.

(4) No splits from end of tie to a point beyond the outside edge of tie plate.

(5) No center-bound break.

(6) No evidence of internal decay.

(7) Tie should have evidence of treatment.

(8) Tie could have surface checks but no checks half way or more through the tie.

j. Salvaged ties must be reinstalled or re-treated as soon as possible after being removed from ballast. If a used tie is allowed to dry out it tends to be subject to excessive checking and/or splitting.

k. Ties unfit for reuse in standard gage track have possible uses as follows:

(1) Fence posts. Some ties removed from track will make satisfactory fence posts.

(2) Narrow gage ties. Cutting off the useless ends of ties will shorten them for reuse in tracks of material, repair, or seasoning yards.

(3) Current retards. Set on end and properly spaced, ties useless in track will divert water and thus control erosion for a period justifying their use for that purpose.

(4) Crib walls. Rectangular ties are more suitable than slab ties for such construction.

(5) Mud sills. Unusable ties serve satisfactorily to support stacks of ties or other material off the ground.

(6) Paving. Where more elaborate paving is not justified on motor car set-offs or in stock yards, unusable ties may provide a durable, serviceable pavement.

(7) Scrap bins. At section houses and elsewhere, ties no longer useful in track can be cribbed to provide receptacles for material to be reclaimed or discarded.

(8) Sale. Local demands for old ties to be used for landscaping, charcoal, fuel, wood chips, blocking and other uses may provide markets which will absorb ties no longer desired by the railroad company.




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SECTION 3.6 WOOD PRESERVING1

3.6.1 FUNDAMENTALS (1985)

Preservative treatment of wood to retard or prevent the effectiveness of wood-destroying agencies such as fungi, bacteria, insects, marine borers, and fire has succeeded in making wood an economical material for use in many fields. The magnitude of annual savings produced by preservative treatment is proportional to the degree of careful attention assigned to the qualityof preservatives, the detail of the treating procedures, the proper handling of the treated material and the competent inspectionof all of these essentials. Heartwood of most naturally durable woods resists penetration by preservative. Yet its life is generally extended by treatment, even though the depth of penetration is slight, providing that the wood is properly seasoned prior to treatment. Preservative treatment will not restore any loss of strength resulting from defects of any kind; consequently, only wood free of significant defects which will render it unfit for use can be treated to advantage.

3.6.2 PREPARATION OF MATERIAL PRIOR TO TREATMENT (2013)

a. If pressure treated wood materials are to give the proper service life, care must be taken to insure that the material has been prepared properly before it is processed. For example, preservatives do not penetrate through any inner bark left on the surface of wood. Inner bark also retards the seasoning of wood. For these reasons, round stock such as poles, piling, and posts should be inspected carefully before it is put out into a seasoning yard or trammed for processing in a cylinder to make sure that the surfaces are free of large patches of inner bark. Standard specifications permit inner bark provided that the strips are not more than 3/4 inch wide and 8 inches long and are separated by at least 1 inch of clear surface between any two strips. Cross ties and other sawn material do not present any problem in this respect.

b. If anti-checking irons such as “S” irons, dowels and nail plates are used to reduce splitting, they should be applied prior to or on arrival of the material at the treating plant or as soon as possible after stacking in the seasoning yard.

c. With the exception of switch ties and other more costly timbers, it is a more common practice to permit splits to occur in the ties during the seasoning process and then selective doweling or end plating only those ties which will be benefited. Hydraulic pressure is used to close the opening created by the split. Then while the split is held closed, (1) two dowels are driven into prebored holes through the tie in a direction parallel to the face, and close to each end, or (2) toothed nail plates are driven into the ends of the tie.

d. Adzing, boring, trimming, branding and/or incising of cross ties, if specified, should be performed prior to treatment, and in accordance with Article 3.1.4 and Article 3.6.2.g. Adzing provides a smooth and true bearing for tie plates and was necessary when it was common to use hewn, rather than sawn, cross ties. When boring for spikes is required, the boring pattern should fit the hole pattern in the tie plates.

e. When it is not to be expected that a pattern bored for spikes will fit the tie plate, then many railroads substitute a specific pattern to be bored into the tie plate area disregarding the pattern in the plates. The purpose of this is to obtain deeper, more general penetration of the preservative in this vulnerable area during subsequent pressure treatment.

f. There are two reasons why some sawn material is incised prior to treatment. First, the cell structure of wood is such that preservatives penetrate the wood farther in a longitudinal direction than in either a radial or tangential direction. This is particularly true of the heartwood in Douglas fir. Incising of this species prior to treatment opens up access ways for the preservative to move longitudinally through the cells of the wood. Incising of this species prior to treatment results in a better treated commodity. Secondly, incising of some species of hardwoods, such as the gums, before seasoning has taken place, reduces the build up of tension stresses in the surface area of material during seasoning. This reduces the width and the depth of the checks that do develop during seasoning. In addition, the checks tend to grow only from one incision to the next along the grain. Therefore, the lengths of the checks are also controlled.

1 References, Vol. 10, 1909, pp. 629, 669; Vol. 11, 1910, part 2, pp. 737, 860; Vol. 15, 1914, pp. 632, 1094; Vol. 27, 1926, pp. 921, 1414; Vol. 28, 1927, pp. 1117, 1427; Vol. 43, 1942, pp. 407, 413, 698; Vol. 47, 1946, pp. 137, 139, 621; Vol. 54, 1953, pp. 702, 704, 1361; Vol. 55, 1954, pp. 545, 1048; Vol. 57, 1956, pp. 444, 1019; Vol. 61, 1960, pp. 417, 1165; Vol. 75, 1974, p. 379; Vol. 86, 1985, p. 9; Vol. 92, 1991, p. 42; Vol. 96, p. 26.

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g. If incising is specified for material over 2 inches in thickness, the pattern used shall be that shown in Figure 30-3-8.(Patterns slightly different are not objectionable if machines constructed prior to 1940 are used). The incising teeth shall be not more than 7/32 inch thick. If the material being incised is less than 5 inches thick but more than 2 inches thick, the incision shall be made to a depth of 3/4 inch in the edges but to a depth of only 1/2 inch in the sides. In pieces 5 inches or more thick, the incisions shall be made to a depth of 3/4 inch on all four sides.

h. While some western species 2 inches and less in thickness are incised for purposes of obtaining penetration, the patterns used generally vary greatly from that shown in Figure 30-3-8. Such material is generally incised to a depth not exceeding 3/8 inch.

i. Any opening that develops in treated wood that penetrates through the treated zone opens up untreated wood to attack by decay. If such occurs, the service life of the piece is shortened. It is, therefore, desirable to reduce the potential for this to occur by performing every milling or framing operation prior to treatment rather than after treatment. For example, bridge ties should be completely framed prior to treatment. Construction timbers should be cut to length and bored for bolt holes prior to treatment. Poles should be gained and bored for crossarms and braces, cut to length and roofed.

3.6.3 CONDITIONING PRIOR TO TREATMENT (2013)

a. Wood needs to be conditioned for preservative treatment by a procedure which will render it receptive to penetration by preservative without reducing its strength. In addition, the conditioning process should be such that the moisture content of oaks is reduced to a level of 50% or less and of the gums and mixed hardwoods to a level of 45% or less. The moisture content of the western softwoods should be reduced to below 30%. The moisture levels shall be determined with a moisture meter, by the toluene extraction method, or by the oven-drying method as specified by the purchaser. Details for the moisture tests can be found in Standard M2, Section 2, of the Standards of the American Wood Protection Association. The objective of such conditioning is to create seasoning checks before treatment if possible rather than have them develop after treatment and possibly expose untreated wood.

b. The southern pines are a special situation. Round stock of this species has deep sapwood which can be penetrated to a depth of 3 inches to 3.5 inches with a simple steam conditioning cycle. Thus, it is not necessary to season round southern pine commodities before treatment to the level that checks are developed. It is generally sound, however, to season sawn southern pine to low moisture content because this type product has heartwood surfaces which can not be penetrated to a depth of more than 1/4 inch.

c. There are three methods commonly used to condition wood prior to treatment. These are air-drying, Boulton drying and live steaming. The first two reduce the moisture content in the outer 1-1/2 inches of the cross section to a level well below the fiber saturation point (25-30%). When this happens, the wood shrinks from the surface inward and a good, desirable checking pattern occurs.

d. Steam conditioning of unseasoned material is generally restricted to the southern pines. It does not reduce the moisture content below the fiber saturation level and thus its use does not develop a checking pattern in the lumber.

Figure 30-3-8. Incising Pattern for Material Over Two Inches Thick




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3.6.3.1 Air Seasoning

a. Historically, the oaks, gums and hardwood species most often have been air seasoned prior to treatment. While it is time consuming, the long service life of treated cross ties is a testament to the successful use of the technique. Air seasoning yards should be located where there is maximum exposure to the sun and to freely circulating air. Low humid areas should be avoided. Good drainage must be maintained and the seasoning yard must be kept free of vegetation, debris and decaying wood.

b. All stacks of seasoning material must be supported on treated or other non-decaying sills. The bottom layer of material shall be supported at least 12 inches off the ground. In warm, humid localities, more space should be provided.

c. Air circulation should be promoted by providing alleys at least 3 feet wide between stacks of material. The yard should be designed such that these alleys are continuous across the seasoning yard. In laying out the design, consideration should be given to the prevailing wind so that the air will flow through the layers of material stacked in the seasoning yard.

d. Open stacking furthers the drying of wood, but satisfactory spacing of the pieces depends on their size, the mean relative humidity and the mean temperature of the locality. In most sections satisfactory seasoning is accomplished by stacking cross ties in layers of 8 to 10 with one tie as a stringer at every other end. This is commonly referred to as the German style. Timbers 5 inches or more thick should be stacked with at least 2 inches of air space between layer. Lumber less than 5 inches thick should be stacked with at least 1 inch between layers. Within each layer, all pieces should be at least 2 inches apart. Stickers of preserved wood or areas of contact brushed with preservatives will reduce the likelihood of a type of decay called “stackburn”.

e. The length of time required to adequately air-dry wood in preparation for its preservative treatment varies with the kind, dimensions, and moisture content when stacked and climatic and site conditions. Consequently, a specific seasoning period must be determined for each particular locality and care taken to assure the treatment of all material before it starts to deteriorate in seasoning stacks.

3.6.3.2 Boulton Drying

a. Boulton drying is increasingly important as the cost of the money tied up in air seasoning cross tie inventories becomes an operating cost factor.

b. Historically, Boulton drying has been used with good success to dry the western softwoods prior to treatment. The seasoning conditions in the cool damp Pacific Northwest often makes air seasoning impractical.

c. The Boulton process can be used just as successfully to condition and dry the oaks, hickories, gums, and mixed hardwoods prior to treatment. It is not desirable to use this process, however, if the lumber or timber item has been partially air seasoned in excess of sixty days as this will result in the product having excessive splits or checks. Care must be taken to determine the moisture content of the material prior to drying. This value should then be used to calculate the amount of water that must be removed during the Boulton drying process.

d. During the Boulton drying process ties shall be trammed with each layer separated by 3/8 inch minimum sticker placed at each end of the ties. To condition by this process, the ties are heated in oil under vacuum in the treating cylinder. The water obtained during the period shall pass through a condenser and be collected in a receiver so that it can be weighed or measured. The light oils that evaporate from the preservative and collect on top of the water are drawn off and returned to the preservative tank. Such boiling is continued until the moisture content of the wood is low enough to allow proper treatment and meet the requirements of A.W.P.A. Standard C6 paragraph 3.1.4.

e. This method results in material having a steeper moisture gradient from the surface to a depth of 2 inches below the surface than is found in an air seasoned tie. It is not known whether this is a plus factor or a minus factor. The gradient does change to that of air seasoned material within a few months after treatment.

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f. One benefit of Boulton Drying is that the material is heated to a temperature of 200 degrees F or more throughout the cross section before treatment. Thus, the preservative stays thin during the subsequent treatment and it is possible to obtain deeper penetration in less time than it is possible to obtain in air seasoned ties. This deeper penetration is not obtained however without using more preservative in the processing operation. Another benefit is that the 200 degrees F temperature sterilizes the wood. Any spore of a fungi that might be present is killed.

3.6.3.3 Steam Conditioning

As a conditioning process used prior to treatment, steam conditioning is limited to southern pine to be treated with creosote orthe oil-borne preservatives, to conditioning western softwood species which are to be treated with one of the water-borne salt preservatives or for thawing ice coated or frozen material prior to treatment. The process does not reduce the moisture contentof material to a level below the fiber saturation point; thus checking of unseasoned but treated material will occur after processing rather than before.

3.6.4 PRESERVATIVES (2014)

3.6.4.1 Preservative Specifications

Specific requirements for the preservative treatment of cross ties and switch ties by pressure processes can be found in the American Wood Protection Association (AWPA) latest edition, Section A (Analysis Methods), U (Use Category), F (Conversion Factor and Correction Tables), M (Miscellaneous) and P (Preservatives) Standards.

The following AWPA Standards are incorporated by reference:

Use Category System StandardsU1: User Specification for Treated Wood, Commodity Specification C: Crossties and SwitchtiesT1: Processing and Treatment Standard, Section C: Crossties and Switchties

Preservative StandardsP1/P13: Standard for Creosote Preservative

P2: Standard for Creosote SolutionP3: Standard for Creosote-Petroleum SolutionP4: Standard for Petroleum Oil for Blending with CreosoteP5: Standard for Waterborne PreservativesP8: Standard for Oil-Borne PreservativesP9: Standards for Solvents and Formulations for Organic Preservative Systems

P18: Nonpressure PreservativesP22: Standard for Ammoniacal Copper Zinc Arsenate (ACZA)P23: Standard for Chromated Copper Arsenate Type C (CCA-C)P25: Standard for Inorganic Boron (SBX)P35: Standard for Pentachlorophenol (PCP)P36: Standard for Copper Naphthenate (CuN)

Hydrocarbon Solvent StandardsHSA: Standard for Hydrocarbon Solvent, Type AHSC: Standard for Hydrocarbon Solvent, Type CHSF: Standard for Hydrocarbon Solvent, Type FHSG: Standard for Hydrocarbon Solvent, Type G




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Analysis Method StandardsA1: Standard Methods for Analysis of Creosote and Oil-Type PreservativesA2: Standard Methods for Analysis of Waterborne Preservatives and Fire-Retardant FormulationsA3: Standard Methods for Determining the Penetration of Preservatives and Fire RetardantsA4: Standard Methods for Sampling Wood PreservativesA5: Standard Methods for Analysis of Oil-Borne PreservativesA6: Standard Method for the Determination of Retention of Oil-Type Preservatives from Small SamplesA7: Standard for Wet Ashing Procedures for Preparing Wood for Chemical AnalysisA9: Standard Method for Analysis of Treated Wood and Treating Solutions by X-Ray Spectroscopy

A12: Wood Densities for Preservative Retention CalculationsA13: Standard Method of Analysis for Acid Number of Naphthenic Acids in Copper Naphthenate A14: Standard Method for Determination of Water-Extractable Copper in Copper NaphthenateA15: Referee MethodsA19: Standard Method for Sample Preparation for Determining Penetration of Preservatives in WoodA22: Standard Method for the Quantitative Determination of Creosote in AWPA P3 Creosote-Petroleum

Oil SolutionsA35: The Determination of the Propensity of a Ready-To-Use Oilborne/Oil-Type Wood Preservative

Treating Solution to Form Stable EmulsionsA40: Standard Methods for Determination of Boron Trioxide in Treating Solutions and Treated Wood by

Potentiometric Titration with Sodium HydroxideA41: Standard Method for Determination of Naphthenic Acid in Copper Naphthenate in Wood and

Treating Solutions by Gas ChromatographyA49: Standard for Determination of Heartwood in Pines and Douglas-fir

Miscellaneous StandardsM1: Standard for the Purchase of Treated Wood ProductsM2: Standard for Inspection of Wood Products Treated with PreservativesM3: Standard Quality Control Procedures for Wood Preserving PlantsM4: Standard for the Care of Preservative-Treated Wood ProductsM6: Brands Used on Forest Products

M19: Standard for Destination InspectionsM22: Standard for Third-Party Agency Evaluation of Inspection Data

Volume and Specific Gravity Conversion Tables for Creosote and Creosote SolutionAbridged Volume and Specific Gravity Correction Tables for Petroleum Oils and Pentachlorophenol and Copper Naphthenate SolutionsVolumes of Round Forest ProductsVolume Correction Table for Creosote-Petroleum SolutionsMiscellaneous Conversion Factors and Correction Tables

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Crossties, Switchties in the AWPA Use category system are as follows:

3.6.4.2 Creosote

Creosote and creosote solutions are EPA-registered, restricted use pesticides used for the protection of wood ties as a primaryprotective treatment against the attack of the wood by decay organisms or termites. Creosote must meet the requirements of AWPA P1/P13 and the formulated creosote solutions must meet AWPA Standard P2 or P3.

3.6.4.3 Oil-Borne Preservatives

Copper naphthenate (CuN) is an EPA-registered, non-restricted use pesticide used for protection of wood ties as a primary protective treatment against the attack of the wood by decay organisms or termites. The solvent used with CuN is No. 2 fuel oil but other carriers meeting American Wood Protection Association (AWPA) Standard HSA can be used. Pentachlorophenol is an EPA-registered, restricted use oil soluble preservative. The solvent used with pentachlorophenol is a No. 2 fuel oil but other penta carriers meeting AWPA Standard HSA or HSG can be used. Copper naphthenate and Penta are not suitable preservatives for wood that may come in contact with marine waters.

3.6.4.4 Water-Borne Preservatives

a. Water-borne preservatives are used for protection of wood ties as either primary or ancillary protective treatment against the attack of the wood by decay organisms or termites.

b. Primary water-borne preservatives, CCA-C and ACZA are EPA-registered, restricted use pesticides generally used if a low odor, paintable, leach resistant product is desirable.

c. Ancillary waterborne preservatives such as Boron compounds (SBX) are EPA-registered, non-restricted use pesticides that do not provide long term protection in exterior applications. Water-borne ancillary wood preservatives shall be used in conjunction with primary wood preservatives, which may include a follow-up application of a primary preservative or added to a primary preservative to enhance protection of wood ties. Refer to AWPA Standard U1 specifications for dual treatment in conjunction with boron compounds.

USE Exposure Use Category CommoditySection

General Ground Contact or Fresh Water 4A CImportant and/or High Decay Ground Contact or Fresh Water 4B CCritical and/or Severe Decay Ground Contact or Fresh Water 4C C

UC4 GROUND CONTACT as defined in the AWPA Book of StandardsUC4A GROUND CONTACT General Use -- Wood and wood-based materials used in contact with the ground, freshwater, or other situations favorable to deterioration. Examples are fence posts, deck posts, guardrail posts, structural lumber, timbers and utility poles located in regions of low natural potential for wood decay and insect attack.UC4B GROUND CONTACT Heavy Duty -- Wood and wood-based material used in contact with the ground, either in severe environments, such as horticultural sites, in climates with a high potential for deterioration, in critically important components such as utility poles, building poles and permanent wood foundations, and wood used in salt water splash zones. This category includes utility poles used in moist temperate climates.UC4C GROUND CONTACT Extreme Duty -- Wood and wood-based materials used in contact with the ground, either in very severe environments or climates demonstrated to have extremely high potential for deterioration, in critical structural components such as land and fresh water piling and foundation piling, and utility poles located in semitropical or tropical environments.




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3.6.4.5 Dual Treatments

Wood ties treated with certain boron compounds, in conjunction with other preservatives, are being used to prevent biological degradation from decay causing fungi and insect attack. There are various delivery methods, boron compounds and retention levels currently in use, and users should satisfy themselves that the product of their choice will meet their needs. The American Wood Protection Association (AWPA) standard covering dual treatment is in AWPA standard U1, Commodity Specification C: Crossties and Switchties.

3.6.5 TREATING PLANT EQUIPMENT (1985)

a. The combination of temperature and pressure used in treatment can result in damage to wood commodities. The lack of adequate vacuum can result in material having less than specified retention or penetration. Thus, thermometers, pressure gages, and vacuum gages must be tested at least annually and more often if there is any evidence of a malfunctioning instrument. Whenever a malfunction can not be corrected by simple adjustment, the instrument must be replaced promptly.

b. Similarly, the accuracy of working tank gages or track scales are important in maintaining the quality of treatment at a location. These, too, must be tested at least annually against a certified tank tape reading.

c. AWPA Standard M-3 “Standard Quality Control Procedures for Wood Preserving Plants” states the accuracy that should be expected from these instruments and gages. Purchasers are entitled to review the results of the periodic testing and/or retesting of instrument and gages to insure they have an accuracy in accordance with this standard.

3.6.6 INSPECTION OF TREATED TIMBER PRODUCTS (2002)

AWPA Standard M2, “Inspection of Treated Timber Products” has been written specifically to outline the authority and responsibility of the inspector employed by the railroad for the purpose of determining that material purchased by the railroadhas been processed properly and that the resulting product will provide long service life.

3.6.7 CARE OF MATERIAL AFTER TREATMENT (2013)

Careless handling of wood after treatment is apt to expose areas not reached by the preservative. Thus, the use of pointed toolsother than end hooks is objectionable.

a. If it is necessary to cut into treated wood the freshly cut surfaces should be further protected by a thorough application of preservative to the freshly cut surface. Further details on this can be found in AWPA Standard M4 - Care of Pressure Treated Wood Products of the Standard of the American Wood Protection Association.

b. Special attention is directed to Section 5 and 6 of this standard which deals with the precautions that should be taken after piles have been cut off to the design elevation and ties which are adzed and bored during the upgrading of a track construction.

3.6.8 USE OF TREATED WOOD (2014)

a. Chemically treated wood used by railroads has been preserved with EPA registered pesticides to protect it from insect attack and decay. Wood treated with these chemicals (creosote, pentachlorophenol, or inorganic arsenicals) should be used only where such protection is important and necessary.

b. These chemicals penetrate deeply into and remain in the treated wood for a long time. Exposure to these chemical compounds may present certain hazards. Therefore, the following precautions should be taken both when handling treated wood and in determining where to use treated wood.

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c. Wood treated with CCA-C, ACZA or SBX may be used in interior places, such as residential wood foundations, industrial or commercial settings and farm buildings. Refer to the Preservative Treated Wood MSDS and Product label for additional limits on use site precautions.

3.6.8.1 Use Site Precautions

a. Wood treated with creosote or creosote solutions may only be used in interior places, such as industrial and commercial settings and farm buildings, if the interiors are well ventilated or an effective sealer is used. Refer to the Preservative Treated Wood MSDS and Product label for additional limits on use site precautions.

b. Wood treated with copper naphthenate or pentachlorophenol may only be used in interior places, such as industrial and commercial settings and farm buildings, if the interiors are well ventilated or an effective sealer is used. Refer to the Preservative Treated Wood MSDS and Product label for additional limits on use site precautions.

c. Wood treated with CCA-C, ACZA or SBX may be used in interior places, such as residential wood foundations, industrial or commercial settings and farm buildings. Refer to the Preservative Treated Wood MSDS and Product label for addtional limits on use site precautions.

3.6.8.2 Handling Precautions

a. Dispose of treated wood by ordinary trash collection or burial. Treated wood should not be burned in open fires or fireplaces. Treated wood may be burned for commercial or industrial applications in accordance with State and Federal regulations.

b. Avoid frequent or prolonged inhalation of sawdust from treated wood. When sawing and machining treated wood, wear a dust mask. Whenever possible, these operations should be performed outdoors to avoid indoor accumulations of airborne sawdust from treated wood.

c. Avoid frequent or prolonged skin contact with pentachlorophenol or creosote-treated wood; when handling the treated wood, wear tightly woven coveralls and use gloves impervious to the chemicals (for example, gloves that are vinyl coated or made of rubber). When power-sawing and machining, wear goggles to protect eyes from flying particles. Wash thoroughly after skin contact, especially before eating, drinking or use of tobacco products. If oily pre-preservatives or sawdust accumulates on clothes, launder before reuse. Wash work clothes separately.

3.6.9 SPECIFIED REQUIREMENTS (2002)

Specified requirements for the preservative treatment of cross ties and switch ties by pressure processes can be found in the American Wood Preservers’ Association (AWPA) Standard C6.

SECTION 3.7 SPECIFICATIONS FOR TREATMENT1

3.7.1 GENERAL REQUIREMENTS (2013)

The following requirements apply to each of the treatment processes. If these requirements are to be modified to meet special conditions, complete detailed instructions shall be given.

1 References, Vol. 21, 1920, pp. 328, 1385; Vol. 27, 1926, pp. 919, 965, 1414, 1415; Vol. 43, 1942, pp. 408, 463, 698; Vol. 54, 1953, pp. 708, 1361; Vol. 55, 1954, pp. 543, 1048; Vol. 57, 1956, pp. 445, 1020; Vol. 59, 1958, pp. 605, 1227; Vol. 62, 1961, pp. 503, 916; Vol. 63, 1962, pp. 322, 743; Vol. 67, 1966, pp. 179, 717; Vol. 69, 1968, p. 338; Vol. 75, 1974, p. 379; Vol. 92, 1991, p. 46; Vol. 96, p. 26.




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3.7.1.1 Plant Equipment

Treating plants shall be equipped with the thermometers and gages necessary to indicate and record accurately the conditions at all stages of treatment, and all equipment shall be maintained in acceptable, proper working condition and meet the requirements of AWPA Standard M-3. The apparatus and chemicals necessary for making the analyses and tests required by the purchaser shall also be provided by plant operators, and kept in condition for use at all times.

3.7.1.2 Incising

When incising is specified, the material shall be incised prior to yarding and seasoning to reduce checking, or if dry prior totreatment on four sides, with incisor not more than 7/32 inch thick to the pattern shown in Figure 30-3-9. In pieces 5 inches or more thick, the incisions shall be 3/4 inch deep. In pieces less than 5 inches but more than 2 inches thick, they shall be 3/4 inch deep in the edges but only 1/2 inch deep in the sides. Incising of pieces 2 inches and thinner is not recommended. Patterns slightly different are not objectionable if machines constructed prior to 1940 are used.

3.7.1.3 Conditioning

a. Material shall be conditioned by air-seasoning, by kiln drying, by steaming, or by heating in the preservative either under vacuum or at atmospheric pressure, or by a combination of them as agreed upon, in such a manner as will not cause damage for the use intended.

b. When air-seasoning is used, the material shall be treated before it begins to deteriorate.

c. When steam conditioning is used, the maximum temperature and the overall maximum duration of steaming shall be as prescribed for the species and type of material in the appropriate AWPA Commodity Standard. The maximum temperatures specified shall not be reached in less than 1 hour. Lower temperatures and shorter steaming periods may be used when agreed to by the purchaser.

d. The cylinder shall be provided with vents to relieve it of air and to insure proper distribution of steam. After steaming is completed, a vacuum of at least 22 inches at sea level shall be drawn.

e. The cylinder shall be relieved continuously or frequently enough to prevent condensate from accumulating in sufficient quantity to reach the wood. Before preservative is introduced the cylinder shall be drained of condensate.

f. When steaming is used solely to preheat the material prior to treatment, the vacuum period may be waived. Ice-coated or frozen material may be steamed prior to conditioning or treatment for a total period not to exceed 2 hours. The temperature shall not exceed 240 degrees F.

g. When conditioning by heating in oil is used, the oil shall cover the material in the cylinder. If a vacuum is drawn during the conditioning period, it shall be of sufficient intensity to evaporate water from the material at the temperature of the oil. The intensity of the vacuum, or the temperature of the oil, or both, shall be adjusted so as to regulate the evaporation of water satisfactorily. The conditioning shall continue until the material is sufficiently heated and enough

Figure 30-3-9. Incising Pattern

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water removed to permit proper penetration. The oil shall be removed from the cylinder before an empty-cell process is applied.

3.7.1.4 Machining

It is preferred that all adzing, boring, chamfering, framing, gaining, incising, surfacing and trimming be done prior to treatment.

3.7.1.5 Sorting and Spacing

Whenever it is practicable, the material in any charge shall consist of pieces similar in size, species, moisture content, and receptivity to treatment and so separated as to insure contact of treating medium with all surfaces.

3.7.2 TREATMENT (2013)

3.7.2.1 Creosote-Type Preservatives

3.7.2.1.1 Manner of Treatment

Following the conditioning period, the material shall be treated by an empty-cell process whenever practicable, to obtain as deep and uniform penetration as possible with the retention of preservative stipulated. Material shall be treated by the full-cellprocess only when the maximum net retention is desired and when pressure is held to refusal, or when the stipulated retention is greater than can be obtained by the use of an empty-cell process. The ranges of pressure, temperature and time duration shallbe controlled so as to obtain maximum penetration with the quantity of preservative injected.

3.7.2.1.2 Empty-Cell–Lowry and Rueping1

a. Material shall be subjected to atmospheric air pressure or to a higher initial air pressure of the necessary intensity and duration. The preservative shall be introduced until the cylinder is filled, the air pressure being maintained constant during the filling operation. The pressure shall be raised to not more than that specified in the appropriate AWPA Commodity Standard. Material shall be held under pressure until there is obtained the largest practicable volumetric injection that can be reduced to the stipulated retention by ejection of surplus preservative from expansion of the air initially introduced and by a quick high vacuum.

b. The temperature of the preservative during the entire pressure period shall be not more than 210 degrees F, but shall average at least 180 degrees F.

c. After the pressure period is completed the cylinder shall be emptied speedily of preservative, and a vacuum of not less than 22 inches at sea level created promptly and maintained until the wood can be removed from the cylinder free of dripping preservative.

d. An expansion bath may be applied after pressure of an oil treatment is completed and before removal of preservative from the cylinder, by quickly reheating the oil surrounding the material to the maximum temperature permitted by the individual species specification, either at atmospheric pressure or under vacuum, the steam to be turned off the heating coils immediately after the maximum temperature is reached. The cylinder shall then be emptied speedily of preservative and a vacuum of not less than 22 inches at sea level created promptly and maintained until the wood can be removed from the cylinder free of dripping preservative.

e. At the completion of the treatment, material may be cleaned by final steaming as specified in the appropriate AWPA Commodity Standard for the individual type of material or species.

1 If the cylinder is filled at atmospheric air pressure, the process is known as Lowry. If initial air pressure higher than atmospheric is used, the process is known as Rueping.




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3.7.2.1.3 Full Cell–Bethel

a. Material shall be subjected to a vacuum of not less than 22 inches at sea level for not less than 30 minutes either before the cylinder is filled or during the period of heating in the preservative. If not already full, the cylinder shall then be filled without first breaking the vacuum. The pressure shall be raised to not more than that specified in the appropriate AWPA Commodity Standard. Material shall be held under pressure until there is obtained the volumetric injection that will insure the stipulated retention, or until the wood is treated to refusal.

b. The temperature of the preservative during the entire pressure period shall be not more than 210 degrees F, but shall average at least 180 degrees F.

c. After pressure is completed, the cylinder shall be emptied speedily of preservative and a vacuum of not less than 22 inches at sea level created promptly and maintained until the wood can be removed from the cylinder free of dripping preservative.



a. Following the conditioning period1, the material shall be treated by the full-cell process as described in Article 3.7.2.1.3. The treating solution shall be of uniform concentration and no stronger than necessary to obtain the required retention of dry salt preservative with the largest volumetric absorption practicable. The ranges of pressure, temperature and time duration shall be controlled so as to obtain the maximum penetration by the quantity of preservative injected.

b. The temperature of the preservative during the entire pressure period shall not be more than 160 degrees F in the case of chromated zinc chloride, or 120 degrees F for acid copper chromate.



a. Following the conditioning period2, the material shall be treated by an empty-cell process as described in Article 3.7.2.1.2. whenever practicable, to obtain as deep and uniform a penetration as possible with the retention of preservative stipulated. Material shall be treated by the full-cell process as described in Article 3.7.2.1.3, only when the maximum net retention is desired and where pressure is held to refusal, or when the stipulated retention is greater than can be obtained by the use of an empty-cell process. The ranges of temperature, pressure and time duration shall be controlled so as to obtain maximum penetration with the quantity of preservative injected.

b. The temperature of the preservative during the entire pressure period shall not exceed the maximum temperatures but shall average at least the minimum temperature as shown in the appropriate AWPA Standards.

c. After pressure is completed, the cylinder shall be emptied of preservative solution and a vacuum of not less than 22 inches at sea level created promptly and maintained until the wood can be removed from the cylinder free of dripping solution.

d. An expansion bath may be applied after pressure of an oil treatment is completed and before removal of preservative from the cylinder, by quickly reheating the oil surrounding the material to the maximum temperature permitted by the individual species specification, either at atmospheric pressure or under vacuum, the steam to be turned off the heating coils immediately after the maximum temperature is reached. The cylinder shall then be emptied of preservative and a

1 If the cylinder is filled at atmospheric air pressure, the process is known as Lowry. If initial air pressure higher than atmospheric is used, the process is known as Rueping.

2 Heating in preservative is not practicable.

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vacuum of not less than 22 inches at sea level created promptly and maintained until the wood can be removed from the cylinder free of dripping preservative.

e. At the completion of treatment by an empty-cell process material may be cleaned by final steaming as specified in the appropriate AWPA Standards for the individual type of material or species.

3.7.3 RESULTS OF TREATMENT (2013)

3.7.3.1 Retention of Preservative

a. The net retention in any charge shall be not less than 90% of the quantity of preservative that may be specified; but the average retention by the material treated under any contract or order and the average retention of any 5 consecutive charges shall be at least 100% of the quantity required, unless specified, and treated to refusal. The amount of preservative retained shall be calculated from reading of working-tank gages, or scales, or from weights before and after treatment of loaded trams on suitable track scales, with the necessary corrections for changes in moisture content, or by the assay method. Recommended minimum retentions for various materials for various uses are contained in the appropriate AWPA Commodity Standard.

b. The retention of oil-borne and water-borne preservatives shall be expressed in pounds of dry preservative per cubic foot. The volume and specific gravity correction tables of the AWPA F Standards shall be used in calculating retention.

c. The volume of oil-borne preservatives shall be calculated on the basis of 100 degrees F. Calculations of volume or weight shall be made by the use of temperature or specific gravity factors contained in the volume and specific gravity correction tables of the AWPA F Standards.

d. The amount of preservative retained shall be in accordance with the appropriate AWPA Standards, unless modified by the purchaser.

e. The penetration of preservative shall be as specified in the appropriate AWPA Standards.

3.7.3.2 Plugging Penetration Test Holes

All holes made for determining penetration of preservative shall be filled with tight-fitting treated plugs.

3.7.4 PRESERVATIVES (2014)

The preservative used shall be whichever of the following specifications is stipulated. See Article 3.6.4 of this Chapter for specific considerations.

3.7.4.1 Creosote-Type Preservatives

a. Creosote.

b. Creosote-Coal Tar Solutions1.

c. Creosote-Petroleum Solutions1.


a. Ammoniacal Copper Zinc Arsenate (ACZA).

1 Retention for creosote-coal tar and creosote-petroleum solutions are based on a 50 percent creosote solution.




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b. Chromated Copper Arsenate (CCA-C).

c. Boron based preservatives (SBX).

d. Ammoniacal Copper Arsenate (ACA) removed due to reformulation to ACZA and no longer available.


a. Copper Naphthenate.

b. Pentachlorophenol.


Inspection for conformity to the requirements of this specification shall be as specified for the individual type of material orspecies as shown in the appropriate AWPA Standards and as specified in Article 3.7.5.1, Article 3.7.5.2 and Article 3.7.5.3.

3.7.5.1 Retention of Preservative

When maximum retention by full-cell process or treatment to refusal is specified, the pressure and temperature shall be maintained constant or increased within a range consistent with good practice for the material being treated until the quantityof preservative absorbed is not more than the following percentages of the amount already injected: All species except Douglas fir and oak–1/2% in any half hour; Douglas fir and oak–2% in each of any 2 consecutive half hours.

3.7.5.2 Penetration

After treatment, the inspector shall examine the charge and select representative material to be bored for determining penetration by the preservative. A boring shall be made by the inspector approximately midway between the ends of each selected piece, avoiding checks, knots, pitch pockets, shakes and splits, except in red oak longer than 9 feet, when the boringshall be approximately 4 feet from either end of the piece.

3.7.5.3 Measurement of Penetration

a. Except in the case of red oak, cores shall be split smoothly, lengthwise across the grain, and depth of penetration and thickness of sapwood measured to the nearest 1/10 inch. The depth of penetration shall be the distance from the outer end of the core to and including the summerwood of the innermost ring showing penetration in its summerwood, provided there are no untreated bands of one or more annual growth rings within the measured distance.

b. In the case of red oak, the number of annual growth rings in the core and the number of rings containing preservative shall be counted. The latter divided by the former will give the percentage of rings penetrated. When any ring appears on the core more than once, each appearance shall be counted. Preservative in any pore or vessel of any annual ring of the core shall class that ring as penetrated. In case of doubt, the questionable ring shall be cut crosswise through the springwood, and if any pore on the cut surface shows preservative for its length the ring shall be considered penetrated. The percentage of rings penetrated in any charge shall be determined by totaling the individual percentage and dividing their sum by the number of cores.

3.7.6 METHODS OF DETERMINING PENETRATION IN WOOD TREATED WITH PRESERVATIVES (2002)

3.7.6.1 General

a. Penetration in material treated with water-borne preservatives shall be determined in accordance with AWPA Standard A3, Standard Method for Determining Penetration of Preservatives.

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b. The depth of penetration in gum lumber and ties shall be the sum of all treated sections appearing on the core.

3.7.7 RETREATMENT (1995)

3.7.7.1 General

Material not conforming to the stipulated minimum requirements may be reoffered for acceptance under the following conditions:

a. Material shall not be retreated more than twice.

b. When material is retreated in a charge with untreated material, the volume of the retreatable material shall not exceed 10% of the total volume of the charge, and in the computation of the required minimum net retention of preservative, all material in the charge shall be considered as untreated.

c. When a charge as a whole is retreated, the total retention as a result of all treatments shall be sufficient to satisfy the specified requirements for both net retention and penetration.

d. When a charge made up for pieces of insufficient penetration only is retreated, the amount of preservative injected during retreatment shall be sufficient to produce the required penetration.

3.7.8 SPECIFIC REQUIREMENTS FOR PRESERVATIVE TREATMENT BY PRESSURE PROCESS (2013)

Refer to the appropriate AWPA Standards for the specific requirements for preservative treatment by pressure processes. The complete list of applicable AWPA Standards is given in Article 3.6.4.1.

SECTION 3.8 RECOMMENDED PRACTICE FOR THE MANUFACTURE OF TWO-PIECE STEEL DOWELED LAMINATED CROSS TIES (TPSDLC)1

3.8.1 MATERIAL (1984)

3.8.1.1 Kinds of Wood

a. Before manufacturing TPSDLC’s, producers shall ascertain which of the following kinds of wood suitable for cross ties will be accepted:

NOTE: All species listed are permitted unless the buyer specifies otherwise. Density requirements on conifers, if any, to be specified by the buyer. (In eastern production areas hardwoods are recommended and should be

1 References, Vol. 85, 1984, p. 10.

Ashes Cypresses Hemlocks Oaks SycamoresBeech Douglas Fir Hickories Pines WalnutsBirches Elms Larches PoplarsCatalpas Firs (true) Locusts RedwoodsCedars Gums Maples SassafrasCherries Hackberries Mulberries Spruces




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grouped as oak and mixed hardwoods.) Each component, half should be from the same species grouping, i.e. oak-oak and mixed hardwood-mixed hardwood.

b. Except as hereinafter provided, all pieces used to make up the TPSDLC’s shall be free from any defects that may impair their strength or durability as TPSDLC components, such as decay, large splits, large shakes, large or numerous holes or knots, grain with slant greater than one in fifteen.

3.8.2 DESIGN (2011)

3.8.2.1 Dimensions

a. Before manufacturing TPSDLC’s producers shall ascertain which of the following lengths, shapes, or sizes will be accepted.

b. Standard gage TPSDLC’s shall be 8'-0", 8'-6", or 9'-0". The length to be specified by the buyer.

c. Except as hereinafter provided, TPSDLC’s shall measure as follows throughout the rail bearing areas. The rail bearing areas as used here and hereafter are defined as those sections of the TPSDLC between 20 inches and 40 inches from its middle:

• Size 5 – 7" × 9", minimum 9 inch faces.

3.8.2.2 General Requirements

a. Except as hereinafter provided, all TPSDLC’s shall be straight, well-manufactured, cut square at the ends, and have the bark entirely removed.

b. After doweling, all TPSDLC’s shall be manufactured such that one 9 inch surface shall be flat, without offset between the two components. An offset of not more than 1/4 inch between the two components shall be permitted on the opposite surface.

3.8.2.3 Doweling

a. Dowels shall be steel, either three of four fluted, and shall be 1/2 inch in diameter with 3/8 inch root diameter. Dowel lengths used shall be 8: inches for 7" × 9" TPSDLC’s.

b. Two dowels shall be required at a point 5 inches from either end and at the midpoint of every TPSDLC, regardless of its length, for a total of six dowels per tie. Dowel holes shall be 3/8 inch in diameter.

c. In a nominal 7 inch thick tie, the dowels will be inserted 4 inches apart, which will place them 1-1/2 inches ±1/8 inch from the top or bottom of the tie.


3.8.3.1 Location

a. Each piece to be used in making up a TPSDLC shall be inspected before being doweled into place. These pieces will be inspected at suitable and convenient places, at point of shipment or at destination, as may be agreed between the supplier and the buyer.

b. Each completed TPSDLC will likewise be inspected at a suitable and convenient place, either at point of shipment or at destination, as may be agreed between the supplier and the buyer.

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3.8.3.2 Tolerances

3.8.3.2.1 Decay

“Blue stain” is not decay and is permissible in any wood.

3.8.3.2.2 Holes

Within the rail bearing areas a large hole is one more than 1/2 inch in diameter and 3 inches deep, excepting one caused by “pipe or stump rot” in cedar. Outside the rail bearing areas a large hole is one having a diameter more than 1/4 inch the widthof the surface on which it appears and a depth of more than 1-1/2 inches. Numerous holes are any number equaling a large hole in damaging effect. Such holes may be caused in manufacture or otherwise.

3.8.3.2.3 Knots

Within the rail bearing areas a large knot is one having an average diameter more than 1/3 inch the width of the surface of thecomponent on which it appears; but such a knot will be allowed if it is located outside the rail bearing areas. Numerous knots are any number equaling a large knot in damaging effect.

3.8.3.2.4 Shakes

Shakes are acceptable provided largest dimension measuring length is not more than 1/3 of width and provided they do not extend nearer than 1 inch to any surface. The procedure illustrated in Figure 30-3-10 shall be used in determining the length of a shake.

3.8.3.2.5 Splits

a. A split is a separation of the wood extending from one surface to an opposite or adjacent surface. In a TPSDLC component, a split no more than 1/8 inch wide and/or 4 inches long is acceptable.

b. Anti-splitting devices will not be allowed on component pieces which have splits exceeding these limits. Such pieces are deemed unacceptable and shall not be used in manufacturing a TPSDLC.

Figure 30-3-10. Determining the Length of Shake




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3.8.3.3 Manufacture

3.8.3.3.1 General

a. All TPSDLC’s will be manufactured from components cut from live trees. A component will be considered straight:

• when a straight line along the top from the middle of one end to the middle of the other end is everywhere at least 1 inch from the edge of the component, and

• when a straight line along a side from the middle of one end to the middle of the other end is everywhere more than 2 inches from the top and bottom of the component.

b. A TPSDLC is not well manufactured when its surfaces are cut into with score marks more than 1/2 inch deep.

c. The top and bottom of the TPSDLC will be considered parallel if any difference in the thickness at the sides or ends does not exceed 1/2 inch.


a. Specified dimensions for TPSDLC’s apply to the unseasoned condition. Specified thickness and widths are considered to be met after conditioning if the TPSDLC’s are not more than 1/4 inch thinner or narrower than the specified sizes. TPSDLC’s over 1 inch thicker or wider than the specified sizes may be rejected. TPSDLC’s over 2 inches longer or 1 inch shorter than the specified lengths may be rejected.

b. Minimum unseasoned component size shall be a full 4-1/2" × 7".

c. All thickness, width, and face dimensions, apply to the rail bearing areas of the TPSDLC. All determinations of the width will be made on top of the TPSDLC, which is the narrower of the horizontal surfaces, or the one with the narrower or no heartwood if both horizontal surfaces are of the same width.

d. Wane appearing anywhere along the joint between components is cause for reject. A maximum of 1 inch wane will be permitted on outside corners not within the rail bearing areas.

e. There must be a tight fit between components. Warp on only one component will be permitted provided it does not exceed 1/8 inch from a straight line after doweling.

3.8.4 DELIVERY (1984)

Place and manner of delivery to be as agreed between supplier and buyer.

3.8.5 SHIPMENT (1984)

Means and manner of shipment to be as agreed between supplier and buyer.

3.8.6 TIE PLATES (1984)

AREMA B punch plates are not recommended. Smooth-bottom plates only should be used with TPSDLC’s.

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SECTION 3.9 SPECIFICATIONS FOR TIMBER INDUSTRIAL GRADE CROSS TIES1

3.9.1 SPECIFICATIONS (2015)

3.9.1.1 Material

3.9.1.1.1 Kinds of Wood

Before manufacturing ties, producers shall ascertain which of the following kinds of wood suitable for cross ties will be accepted:

3.9.1.2 General

All procedures regarding quality, manufacture, inspection, shipment, and delivery will comply fully with those specified for grade cross ties in Part 1, General Considerations unless excepted by information contained in this part.

3.9.1.3 Classification and Design

a. Refer to Table 30-3-2 for the allowable sizes, lengths, minimum faces and tolerances.

b. The above minimum face requirements apply to the rail-bearing areas, which are the areas between 20 inches and 40 inches from the middle of the industrial grade cross ties. Outside the rail-bearing areas, up to 5" of wane is allowed on each surface. The grade of each tie shall be determined at the point of most wane, on the top or bottom, within the rail-bearing areas. (The top is defined as the horizontal face farthest from the heartwood or pith center.)

c. Dry or treated ties may be 1 inch narrower or 1/2 inch thinner than the specified sizes. Thickness and width may not vary more than 1 inch from end to end. The tie body may be out of square by no more than 1 inch throughout the length. Tie length may vary from +6 inches to –6 inches for 9’ and 8’6" ties, and +6" to -2" for 8’ ties.

1 References, Vol. 94, p. 65.

Ashes Elms Larches PoplarsBeech Firs (true) Locusts RedwoodsBirches Gums Maples SassafrasCatalpas Hackberries Mulberries SprucesCherries Hemlocks Oaks SycamoresDouglas Fir Hickories Pines Walnuts

Table 30-3-2. Requirements for Cross Ties

Grade Dimensions Minimum Faces Allowed

6 inch IG 6" × 8" × 8'-0" / 8'-6" 6 inch face on top or bottom7 inch IG 7" × 8" × 8'-0" / 8'-6" 6 inch face on top or bottom7 inch IG 7" × 9" × 8'-0" / 8'-6" 6 inch face on top or bottom




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3.9.1.4 Definitions of Defects

3.9.1.4.1 Wane

Wane is defined as bark or the lack of wood (see Article 3.9.1.3 for allowance).

3.9.1.4.2 Decay

Ties with decay greater than 1-1/2 inches in diameter within the rail bearing areas will be rejected. Slight incipient decay willbe allowed if the tie as a whole is of good quality. Decay is allowed outside of the rail bearing areas if the decayed area doesnot exceed 3 inches in diameter. Ties with decay greater than 2 inches in diameter appearing in both ends of the tie will be rejected.

3.9.1.4.3 Holes

Ties having holes on any surface within the rail bearing areas greater than 1-1/2 inches in diameter or greater than 3 inches deep will be rejected. Ties with holes on any surface outside the rail bearing areas greater than 3 inches in diameter or deeperthan 4 inches will be rejected. Numerous holes are any number equaling a large hole in damaging effect and will be cause for the tie to be rejected.

3.9.1.4.4 Knots

A knot greater than 3 inches in diameter within the rail-bearing area will not be permitted.

3.9.1.4.5 Shakes

Shake that is not more than 5 inches in length will be allowed. Shake may appear on one face or both ends as long as it does not run the entire length of the tie. Length measurments shall be made using Figure 30-3-10 as a guide. If end plates are used they must be mechanically applied to insure they are fully seated for maximum performance.

3.9.1.4.6 Splits

A split is a separation of wood extending from one surface to an opposite or adjacent surface-not counting the end as a surface.A seasoned or treated tie with a split greater than 1/2 inch wide or 11 inches long will be rejected unless a nail plate has beenproperly applied.

3.9.1.4.7 Checks

A check is a separation of wood due to seasoning which appears on one surface only-not counting the end as a surface. Season checks greater than 2 inches deep or 3/4 inch wide shall be rejected as industrial grade ties.

3.9.1.4.8 Cross or Spiral Grain

Except in species with interlocking grain, ties having cross, slant, or spiral grain greater than 2 inches in 15 inches of lengthwill be rejected.


Bark seams will not be acceptable if more than 2 inches deep or more than 10 inches long anywhere in the tie.


All ties must be straight and have top and bottom parallel. Any ties which do not meet the following characteristics of good manufacture will be rejected:

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a. A tie will be considered straight when a straight line from a point on one end to a corresponding point on the other end is no more than 2 inches from the surface at all points.

b. The top and bottom of a tie will be considered parallel if any difference at the sides or ends does not exceed 1 inch.

c. A tie is not well-sawn when its surfaces are cut with scoremarks more than 1 inch deep.

d. For proper seating of nail plates, tie ends must be flat, and will be considered square with a sloped end of up to 1/2 inch, which equals a 1 in 20 cant. When nail plates are applied they must be fully seated and flush with the end surface. If corners of nail plates are exposed, they must be pounded flat over the corner of the tie to reduce the danger of injury to personnel handling the ties.

3.9.1.5 Delivery




All ties are at the owners risk until accepted. All rejected ties shall be removed within one month after inspection.

3.9.1.6 SHIPMENT

Ties forwarded in cars or vessels shall be separated therein according to the above groups (Table 30-3-2), and also according to the above sets or lengths if inspected before loading, or as may be stipulated in the contract or order for them.


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30Part 4

Concrete Ties1

— 2015 —

FOREWORD

These recommendations cover materials, physical dimensions, vertical design loads, structural strength, and other considerations for prestressed monoblock and conventionally reinforced two-block concrete ties. Unique requirements for turnout ties and grade crossing ties are included.

In addition, the following are provided: Longitudinal and lateral load restraint requirements, electrical performance requirements of rail fastener and tie combinations, shipping, handling, disposal, application and use.

Laboratory tests for the suitability of new designs are specified, as are tests for monitoring quality-control during manufacture.These recommended practices cover a number of manufacturing tolerances; however, they do not cover techniques or equipment for the manufacture of concrete ties or fastenings.

For definitions applicable to these recommended practices refer to the Chapter 30 Glossary located at the end of this Chapter.

TABLE OF CONTENTS


4.1 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-44.1.1 Introduction (1992) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-44.1.2 Vertical Loads (2011) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-44.1.3 Lateral Loads (2015) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-74.1.4 Longitudinal Loads (1992). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-74.1.5 Rail Seat Loading Distribution (2015). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-84.1.6 Rail (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-84.1.7 Rail Seat Abrasion (RSA) (2014). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-9

1 References, Vol. 77, 1976, p. 193; Vol. 78, 1977, p. 133; Vol. 83, 1982, p. 192; Vol. 84, 1983, p. 97; Vol. 85, 1984, p. 40; Vol. 86, 1985, p. 68; Vol. 87, 1986, p. 98; Vol. 89, 1988, p. 124; Vol. 91, 1990, p. 87; Vol. 92, 1991, p. 63; Vol. 94, 1993, p. 76, Vol. 97, p. 114. Reapproved with addition of metric equivalents 1996.

Ties





4.2 Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-114.2.1 General (2003) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-114.2.2 Concrete (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-114.2.3 Duggan Concrete Expansion Test (1993). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-134.2.4 Metal Reinforcement (2003) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-14

4.3 Tie Dimensions, Configuration and Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-164.3.1 Special Considerations (1992) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-164.3.2 Requirements (2007) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-16

4.4 Flexural Strength of Prestressed Monoblock Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-194.4.1 Flexural Performance Requirements for Prestressed Monoblock Designs (2014) . . . . . . . . . . . . . . 30-4-194.4.2 Design Considerations (1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-224.4.3 Test Requirements For Approving the Design of a Monoblock Tie (1988). . . . . . . . . . . . . . . . . . . . 30-4-22

4.5 Flexural Strength of Two-Block Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-234.5.1 Flexural Performance Requirements For Two-Block Designs (1988). . . . . . . . . . . . . . . . . . . . . . . . 30-4-234.5.2 Test Requirements for Approving the Design of a Two-Block Tie (1993) . . . . . . . . . . . . . . . . . . . . 30-4-24

4.6 Longitudinal Rail Restraint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-244.6.1 Requirements (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-24

4.7 Lateral Rail Restraint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-244.7.1 Rail Fastening Requirements (2015) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-24

4.8 Electrical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-274.8.1 Requirements (1990) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-27

4.9 Testing of Monoblock Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-274.9.1 Design Test of Monoblock Ties (2014) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-274.9.2 Production Quality Control of Monoblock Ties (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-34

4.10 Testing of Two-Block Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-354.10.1 Design Tests of Two-Block Ties (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-354.10.2 Production Quality Control of Two-Block Ties (1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-39

4.11 Recommended Practices For Shipping, Handling, Application and Use. . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-404.11.1 Shipping (1989) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-404.11.2 Handling (1989) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-404.11.3 Placement and Initial Roadbed Support (1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-404.11.4 Placement of Rail and Fastenings in New Construction (2005). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-404.11.5 Tamping (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-414.11.6 Track Geometry (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-414.11.7 Serviceability (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-41

4.12 Ballast. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-424.12.1 Scope (1996). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-42

4.13 Ties for Turnouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-42

Concrete Ties



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4.13.1 General (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-424.13.2 Layout (1993). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-424.13.3 Tie Dimensions (1993). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-444.13.4 Design Considerations (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-454.13.5 Flexural Strength (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-454.13.6 Support Conditions (1993). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-454.13.7 Tolerances (1993). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-47

4.14 Ties for Grade Crossing Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-474.14.1 General (2005) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-474.14.2 Design (2005). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-48

4.15 Cast-In and Post-Installed Inserts for Concrete Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-48

4.16 Concrete Tie Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-494.16.1 Shoulder Replacement or Repair (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-494.16.2 Railseat Abrasion Repair (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-49

Commentary (2015) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-50

LIST OF FIGURES


30-4-1 Estimated Distribution of Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-630-4-2 Duggan Core Treatment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-1330-4-3 Unfactored Bending Moment at Centerline of Rail Seat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-2030-4-4 Tonnage and Speed Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-2130-4-5 Bending Moment – Reinforced Two-Block Ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-2530-4-6 Bending Moment – Prestressed Two-Block Ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-2630-4-7 Rail Seat Negative Moment Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-2930-4-8 Rail Seat Positive Moment Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-2930-4-10 Tie Center Negative Moment Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-3130-4-11 Tie Center Positive Moment Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-3230-4-12 Insert Pullout Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-3230-4-13 Two Block Tie Center Negative Bending Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-3730-4-14 Two Block Tie Center Positive Bending Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-3830-4-15 Tie Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-4330-4-16 Preferred Rotation Method for Shoulders in Turnout Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-4430-4-17 Ties in Crossovers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-46

LIST OF TABLES


30-4-1 Bending Moment Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-1930-4-2 Negative Bending Moments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-2330-4-3 Allowable Crack Widths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-4-24

Ties



SECTION 4.1 GENERAL CONSIDERATIONS


a. In supporting and guiding railway vehicles, the track structure must restrain repeated lateral, vertical and longitudinal forces. As elements of the track structure, individual cross ties receive loads from the rails or fastenings and in turn transmit loads to the ballast and subgrade. Consequently, the design of a tie affects and is affected by characteristics of other components of the track structure. The use of concrete railway ties introduces different considerations into the design and installation of track systems. When such systems are properly designed and the component parts properly interrelated, installed and maintained, concrete railway tie systems can provide track of superior quality.

b. The analysis of requirements for such systems must necessarily involve not only the tie but all components of the track system, their interdependency and the conditions under which they must be applied. Thus, concrete tie track systems involve:

• The rail, tie fastenings, ballast, subgrade and base,

• The quality of each component, method of manufacture, installation and maintenance,

• The direction, magnitude and frequency of traffic-imposed loads; the effect of environmental factors such as temperature and weather and the overall economics of installation and maintenance, and

• The need to support and guide railway vehicles while restraining repeated lateral, vertical and longitudinal forces.

c. The performance specifications which follow provide the basic guidance needed in the selection, design and application of concrete tie systems. Success in their application will require careful supervision on the part of the engineer to ensure that all components meet required standards and that the system is properly installed and maintained.

4.1.2 VERTICAL LOADS (2011)

4.1.2.1 Tie Spacing

a. The spacing affects rail flexure stress, compressive stress on ballast and roadbed and the flexure stress generated in the ties themselves. For a given set of tie dimensions and wheel loads, the consequences of increasing tie spacing are higher rail bending moments and stresses within the individual ties. For the case of constant tie, ballast and subgrade characteristics, wider tie spacings bring about larger track depression per unit of wheel load, i.e. lowered track modulus. Conversely, reduction of tie spacing lowers unit stress and increases track modulus.

b. These specifications cover concrete ties intended for track designs using center-to-center spacings of cross ties of between 20 inches and 30 inches, (510 and 760 mm).

4.1.2.2 Cross Tie Dimensions

a. Use of longer, wider, or stiffer ties which increase the tie-to-ballast bearing area has many of the same effects as reducing tie spacing. There are, however, limits beyond which an increase in tie size is ineffectual in reducing track stress and increasing track modulus. The concentration of tie-to-ballast load decreases with lateral distance from the rail. The rate of decrease of load with distance is higher for flexible tie materials and designs. There is, therefore, a point beyond which lengthening tie design will fail to significantly reduce unit bearing load. There are, in addition, right-of-way clearances and machinery limitations which restrict tie length.

b. Widening tie design has similar benefits to increases in tie length. Widening tie design, however, beyond the point where it is practical to compact ballast beneath the tie is ineffective.

Concrete Ties



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c. These specifications cover tie designs between 7 -9 and 9 -0 (236 and 274 cm) in length and between 8 inches and 13 inches (20 and 33 cm) in width at their bottom surface. Because of bond transfer, pretensioned concrete ties shall be at least 8 -0 (244 cm) long unless additional provisions are made to ensure adequate bond transfer.

4.1.2.3 Load Distribution

The foregoing discussion and the requirements following are based on the knowledge that wheel loads applied to the rail will be distributed by the rail to several ties. This distribution of loads has been confirmed in field investigations. The distributionof load is dependent upon tie and axle spacing, ballast and subgrade reaction, and rail rigidity. The percentage of wheel-to-railload carried by an individual tie varies from location to location. A conservative estimate of the distribution is given in Figure 30-4-1. While rail stiffness does influence these percentages, its effect is small compared to other factors. For the sake of simplification, the distribution factors are shown only as a function of tie spacing. The values chosen are intended to offsetvariations resulting from other influences.

4.1.2.4 Impact Factors

The requirements of these specifications are based on calculations including an assumed impact factor. This factor is a percentage increase over static vertical loads intended to estimate the dynamic effect of wheel and rail irregularities. An impact factor of 200% has been assumed.

4.1.2.5 Ballast and Subgrade

In addition to tie size and spacing, ballast depth and subgrade modulus are also significant in the manner a particular track design restrains vertical loading. Increasing ballast depth tends to spread individual tie loads over a wider area of subgrade,thereby reducing the unit subgrade load and consequent track depression. Thus the effect of increased ballast depth can be similar, within limits, to that of reduced tie spacing. Stiffer subgrades do not require as low a ballast pressure as more flexiblesubgrades. Consequently, they are better able to tolerate wider tie spacings, smaller ties, more shallow ballast depths, or allthree without failure or excessive track depression.

4.1.2.5.1 Ballast and Ballast Pressure

The engineer must insure that the design of track does not result in over-stress of ballast or subgrade. To do so, considerationmust be given to wheel loads, distribution factor, impact factor, unit bearing capacities of the ballast and subgrade, and to crosstie dimensions and spacing.

4.1.2.5.1.1 Ballast Pressure

a. While tie-to-ballast pressure is not uniformly distributed across or along the bottom of a cross tie, an approximate calculation can be made of “average” pressure at the bottom of the tie. The average pressure at the tie bottom is equal to axle load, modified by distribution and impact factors, and divided by the bearing area of the tie:

(See Example 1)

where:

P = Wheel load in pounds (kN)IF = Impact factor in percent

DF = Distribution factor in percent (from Figure 30-4-1)A = Bearing area of cross ties in square inches (millimeters)

Average Ballast Pressure, psi (MPa) 2P 1 IF

100---------+ DF

100---------

A---------------------------------------------------=

Ties



Figure 30-4-1. Estimated Distribution of Loads

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b. The recommended ballast pressure should not exceed 85 psi (0.586 MPa) for high-quality, abrasion resistant ballast. If lower quality ballast materials are used, the ballast pressure should be reduced accordingly.

Example 1:

Given 8 -6 long by 11 inches wide (259 cm long by 28 cm wide) concrete ties, what is the calculated value of bearing pressure for a coal car with 39,000-lb (173 kN) wheel load if the ties are to be spaced at 24 inches (610 mm).

NOTE: This example uses an impact factor of 125%. Actual impact factor should be determined based on operating conditions and is not the same impact factor as used for tie flexural design.

4.1.2.5.1.2 Subgrade Pressure

The pressure exerted by ballast on the subgrade depends upon the tie-to-ballast pressure, the load distribution pattern throughthe ballast, and the depth of ballast. Refer to Section 4.12, Ballast.

4.1.3 LATERAL LOADS (2015)

a. The lateral loads generated by moving railway equipment are applied by wheel treads and flanges to the rails, which in turn must be held in place by fastenings, ties, and ballast.

b. Lateral stiffness of rail distributes lateral loads to fasteners and their ties. Structural strength of fastenings and ties holdthe rail to gage. The mass of ties, friction between the ties and ballast, lateral bearing area of ties (end surface), and the mass of ballast all act to restrain lateral tie movement.

c. Lateral track stability can be increased by decreasing tie spacing of ties of similar dimensions, increasing tie mass, increasing end bearing area of ties per unit length of track, and by increasing frictional resistance between ties and ballast.

d. Structural strength of fastenings must be commensurate with the lateral load individual ties restrain, which in turn is determined by lateral rail stiffness, tie spacing, frictional characteristics of the fastening system, and lateral fastening system stiffness.

e. The magnitude of lateral loads which must be restrained depends not only upon the dimensions, configuration, weight, speed and tracking characteristics of the equipment, but also upon the geometric characteristics of the track structure. Both the gross geometry-whether the track is straight, curved or how sharply curved, and the detail geometry, the irregularities and small deviations from design, influence the magnitude of lateral load.

f. These specifications cover fasteners capable of restraining individual lateral wheel-to-rail loads of up to 14 kips (63 kN) per linear foot (305 mm) of track when these lateral loads are accompanied by vertical loads of a similar magnitude.

4.1.4 LONGITUDINAL LOADS (1992)

The longitudinal load developed by the combination of thermal stress in continuous welded rail and by traffic is transferred bythe fastenings to the ties and ultimately restrained by mass internal friction of ballast. Consequently, the longitudinal bearing

Average Ballast Pressure psi (kPa) 2P 1 IF

100---------+ DF

100---------

A---------------------------------------------------=

78 000 2.25 0.50102 11

-------------------------------------------------=

78.2 psi (0.539 MPa)=

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area (side area) of ties per unit of track length, friction between bottom of ties and ballast, and physical properties of ballastultimately determine the track resistance to longitudinal movement. Resistance to rail movement with respect to ties is determined by the characteristics of fasteners. While total restraint of longitudinal rail movement is generally desirable, thereare situations where such restraint is impractical or undesirable. In conventional track construction, the limiting factor in longitudinal restraint is most often ballast resistance.

4.1.5 RAIL SEAT LOADING DISTRIBUTION (2015)

The distribution of vertical loads at the rail seat can be highly non-uniform1. At high L/V force ratios, the gauge side of the rail seat may become completely unloaded and the field side of the rail seat must bear the entire rail seat load. Factors affecting theseverity of the load concentration include L/V force ratio, magnitude of vertical wheel load, crosstie support conditions, and fastening system characteristics such as pad stiffness, fastener clamping force, and component manufacturing tolerances. It is recommended that the increased demands generated by these load concentrations are considered in the design process.

4.1.6 RAIL (1993)

4.1.6.1 Flexure Requirement

The interaction of rail and ties has been discussed in Article 4.1.3 and Article 4.1.4 with respect to distribution factors, tie spacing, and vertical loads. The flexure stress generated in rail under load is a function of applied bending moment and the section modulus of rail. Rail bending moment is in turn determined by wheel load, axle spacing, and track modulus. Most modern rail sections are capable of bearing current wheel loads on tie spacings of up to 30 inches (760 mm) with normal ballast support without distress. It is recommended that the engineer calculate the maximum bending stress for rail sections lighter than 100 lb/yd (49.6 kg/m), if their use is anticipated. The following equation may be used for this purpose:

(See Example 2)

where:

Example 2:

Given track modulus of 3,000 lb/inch/inch and 90 lb RA-A and with I = 38.7 inches4 (1615 cm4) and C = 2.54 inches, (65 mm) what tensile stress is developed under a 30,000 lb (13,608 kgf) wheel load?

1 Greve et al. 2014. Analysis of the Relationship Between Rail Seat Load Distribution and Rail Seat Deterioration In Concrete Crossties. In: Proceedings: ASME Joint Rail Conference, Colorado Springs, CO, April 2014

S = Maximum fiber stress in rail, psi, (MPa)c = Distance from neutral axis to outer edge of base or head, inches, (mm)I = Moment of inertial of rail sections, inches4, (mm4)

E = Modulus of elasticity of steel, psi, (MPa) = Track modulus, pounds/inch/inch, (MPa)

P = Wheel force, pounds, (N)

S McI

-------- PcI

------ EI64---------4= =

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= Bending moment, inch-pounds, (mm-N)1

4.1.6.2 Rail Joints

a. To achieve the maximum benefits and economy from the use of concrete railroad ties it is recommended that, in main-line track, they be used in conjunction with continuous welded rail. If concrete ties are used in conventional bolted track or at the ends of continuous welded rail, care should be exercised to see that the juncture of two rails does not occur over a concrete tie. The magnitude of impacts on a tie placed under the juncture of two rails could be destructive to the rail seat and fastenings.

b. It is recommended that concrete ties not be installed within the limits of insulated joints or within the limits of special timber dimensions of turnouts and crossovers.

4.1.7 RAIL SEAT ABRASION (RSA) (2014)

4.1.7.1 Definition

Rail seat deterioration (RSD), commonly referred to as rail seat abrasion (RSA), is the degradation of material immediately beneath the rail base and rail pad assembly that serves as the bearing surface on concrete crossties. RSD is a problem known to occur on heavy-haul railroads. It has not been reported to be an issue on other rail systems (light rail, commuter rail, transitsystems) in North America. Several mechanisms, or physical processes, have the potential to drive RSD and they have been identified and defined in Article 4.1.7.2.

Demanding service conditions, such as high annual gross tonnages, sharp curvature, and steep grades, contribute to the high stresses at the rail seat that can lead to rail seat deterioration, especially in the presence of moisture. Wear of the fasteningsystem components will result in a reduction in the clamping force and increased motion of the rail pad assembly relative to the concrete rail seat. Various environmental factors and train operating characteristics also affect the presence of moistureand abrasive fines at the rail seat.

If not controlled or repaired, RSD can gradually deteriorate the rail seat of a crosstie such that it can no longer properly supportand restrain the rail, leading to track geometry deficiencies, crosstie maintenance and/or replacement, and the potential for aderailment.

4.1.7.2 RSD Mechanisms and Causes2

The rate of RSD and the primary causes of these mechanisms are related to one or more of the following: high stresses, relativemotion, the presence of moisture, and abrasive fines. Industry experience has indicated that the presence of moisture is directly correlated to the severity of RSD. High lateral and longitudinal forces, such as those experienced in areas of sharp curvature or steep grades on heavy-haul lines, lead to increased stresses localized on the field side of the rail seat.

1 First Progress Report of the Special Committee on Stresses in Track, Vol. 19 AREMA proceeding, p 887.2 See References 1, 7 and 11.

S PcI

------ EI64---------4=

30 000 2.5438.7

--------------------------------- 30 10 6 38.764 3 000

----------------------------------------4=

1968.9 6046.84 17 362 psi==

EI64---------4

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Ongoing research efforts are intending to identify and understand the mechanisms that can contribute to RSD. Some possible mechanisms have been identified to date and include the following:

• Abrasion can occur at the rail seat interface due to relative movement between the rail pad assembly and the rail seat, and it is accelerated when moisture and abrasive fines (sand, deteriorated concrete particles, etc.) are present.

• Localized crushing can occur when concentrated stresses on the rail seat exceed the strength or fatigue limits of the rail seat materials.

• Hydraulic pressure cracking can occur when rail seat loads and water create damaging pore pressure in the concrete.

• Hydro-abrasive erosion can occur when abrasive fine particles are expelled through the action of accelerated water flow (jetting).

• Freeze-thaw cracking can occur when the tensile strength of the concrete is exceeded by stresses due to volumetric changes of water in the concrete pore structure.

4.1.7.3 General Recommendations to Mitigate RSD

RSD is a problem known to occur on heavy-haul railroads. Experience gained from revenue service on heavy-haul railroads and RSD experiments conducted at the Transportation Technology Center Incorporated (TTCI) in Pueblo, CO and at the University of Illinois at Urbana-Champaign (UIUC) indicate that possible ways to mitigate RSD are:

• Reducing contact stresses at the rail seat

• Reducing the relative movement at the rail seat

• Increasing the abrasion resistance of rail seat materials

• Designing the fastening system such that the intrusion of abrasive fines and moisture is delayed

• Performing track maintenance and inspection

4.1.7.4 Comments

a. Concrete Ties: The concrete tie rail seat shall be produced within tolerances specified in Section 4.3. The rail seat surface must have a clean and smooth plane with a minimum of form lines, sealing gasket marks, and surface voids or deformations.

b. Pads and Insulators: Pad and insulator wear has a direct influence on the amount of relative displacement at the rail seat, thus affecting the rate of rail seat deterioration and susceptibility to premature failure of the fastening system. Fastening system component design should consider loading and environmental factors.

c. RSD Inspection and Allowable Limits: Please refer to FRA 49 CFR Part 213.234 Requirements – automated inspection of track constructed of concrete crossties for information regarding RSD inspection and allowable limits.

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SECTION 4.2 MATERIAL

4.2.1 GENERAL (2003)

Utmost consideration shall be given to concrete properties affecting durability. Mix design, chemical reactivity, manufacturing methods, material properties, and curing practices affect concrete performance and durability. Past experiences with alkali-aggregate reactivity, air-entrainment, other admixtures, sulfate reactions, alkali-silica reactivity (ASR), and delayedettringite formation (DEF) have influenced the requirements given in this section.

4.2.2 CONCRETE (2014)

The minimum 28-day-design compressive strength of concrete used for concrete ties shall be 7,000 psi (48 MPa) as determined by ASTM Method of Test C 39. The Test cylinders shall be made and stored as specified in ASTM Specification C 31.

4.2.2.1 Cement

a. Cement shall be portland cement and shall meet the requirements of ASTM Specification C 150. It is recommended that cement alkali content of Na2O equivalent (Na2O + 0.658 K2O) be as low as possible and not greater than 0.6%.

b. Alternatively, instead of using low alkali cement to minimize the risk of alkali-aggregate reactivity, pozzolanic materials such as fly ash, silica fume, or slag may be used, provided concretes made from the proposed cement, aggregates, and pozzolan have a demonstrable and proven durability record. As concrete durability problems may not become evident for some time, it is recommended that a minimum service record of 10 years be used to assess performance.

c. Cement mill certificates should be obtained on a regular basis during tie production in order to ensure consistency in chemical ingredients. Under no circumstances shall substitution of cement be permitted unless it has been pre-qualified through the tests listed in this section.

4.2.2.2 Aggregates

a. Both fine and coarse aggregates shall meet the requirements of the AREMA Specifications for Aggregates, Chapter 8, Concrete Structures and Foundations, Part 1, Materials, Tests and Construction Requirements, Section 1.3, Other Cementitious Materials.

b. In addition, for preliminary screening, a field review of aggregate performance in existing concrete structures should be conducted, preferably by an experienced petrographer, to determine the historical durability record. Petrographic analysis according to ASTM C 295 shall be conducted on each new aggregate source, including new faces or strata in existing pits/quarries, to determine potentially reactive mineral constituents. Analysis shall be repeated at six-month intervals. It may also be desirable to retain the service of a professional geologist.

c. Fine and course aggregates shall be hard, strong, durable, and free of deleterious material. Attention shall be given to the requirements of ASTM C33, Section 7.3, Section 11.2, and Appendix XI regarding durability. Coarse aggregates shall meet ASTM C33 Table 3, Class 4S requirements. Aggregates shall be shown to be free from excessive expansion as outlined in 4.2.2.6, Durability of Cured Concrete.

4.2.2.3 Mixing Water

Mixing water shall meet the requirements of the AREMA Specifications for Mixing Water, Chapter 8, Concrete Structures and Foundations, Part 1, Materials, Tests and Construction Requirements, Section 1.5, Water. In addition, the mixing water, including that portion of the mixing water contributed in the form of free moisture on the aggregates, shall not contain deleterious amounts of chloride ion1.

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4.2.2.4 Admixtures

Chemical admixtures for concrete shall conform with ASTM C 494. Additives containing chlorides shall not be used. Where ties will be exposed to freeze-thaw conditions, an air entraining agent according to ASTM C 260 shall be used. As a guide, freeze-thaw durability can generally be obtained with 4.5% minimum air in the wet concrete, 3.5% minimum air-void-content in the hardened concrete, and an air-void spacing factor not exceeding 0.008 inch (0.20 mm).

4.2.2.5 Curing

It is recommended that the concrete be cured by a method or procedure such as set forth in the PCI Manual for Quality Control (MNL116, latest edition), modified as follows:

After placing and consolidating the concrete, the exposed surface shall be covered with impermeable sheeting. Concrete shall not be placed in forms whose temperatures are less than 40 degrees F and the concrete temperature shall not be allowed to fall below 50 degrees F between casting and transfer of prestress.

During the preset period, the concrete temperature shall not exceed 90 degrees F (32 degrees C) during the first 3 hours and 105 degrees F (40 degrees C) during the first 4 hours. With accelerated heat curing, the heating rate shall not exceed 35 degrees F (19.4 degrees C) per hour and the curing temperature within the concrete shall not exceed 140 degrees F (60 degrees C), unless the supplier can demonstrate that the materials used would be satisfactory for long-term durability, in which case temperatures up to 158 degrees F (70 degrees C) may be used.

The heating method used shall be such that all ties produced for a given cast are at a similar temperature. During curing, thetemperature at the center of the rail seat cross section of one tie in each bed shall be automatically recorded.

4.2.2.6 Durability of Cured Concrete

Issues concerning the durability of concrete ties generally relate to two areas of consideration, material expansion and environmental effects. Included here are brief descriptions of several of these issues, and applicable tests that will provideindications of durability.

NOTE: Specifiers should read the description of each issue and its related test carefully, and select only those tests that correspond to the product being specified.

The first area of concern is concrete that fails due to expansion within the concrete matrix. Moisture and chemical incompatibility must be present for expansion to occur. Current known causes are Alkali Silica Reactivity (ASR), Alkali Carbonate Reactivity (ACR), and Delayed Ettringnite Formation (DEF).

Alkali reactivity relates to chemical compatibility between cement and aggregate.

Alkali reactivity is a combination of the total mix alkali content and aggregate reactivity. The appropriate test depends on thetype of aggregate. Petrographic analysis of the aggregates proposed for concrete usage per ASTM C295 and petrographic analysis of the hardened concrete per ASTM C856 combined with the following tests can be useful in determining the potential for alkali aggregate reactivity. Silica based aggregate reactivity (ASR) can be tested by ASTM C1260 (2 week test) and/or ASTM C1293 (1-2 year test). Potentially reactive aggregates may still be acceptable when combined with supplementary cementitious materials and/or with cements with total alkalies less than 0.6% as needed to pass ASTM C1567 and/or ASTM C1293 modified with materials to match the job mix. Carbonate based alkali aggregate reactivity (ACR) can be determined by ASTM C1105. Six-month intervals are recommended for durability tests to ensure ongoing aggregate suitability, or for any new aggregate source.

1 A chloride ion content greater than 400 ppm might be considered detrimental, and it is recommended that levels well below this value be maintained if practicable.

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Delayed Ettringite Formation (DEF) is commonly used to refer to the reformation of ettringite after the initial curing of the concrete, resulting in expansive failure. Two potential causes are excessive sulfate content in the cement or excessive temperatures during the concrete curing process. To test for either situation, the Duggan Test (4.2.3 Duggan Concrete Expansion Test (1993)) is currently the only known method.

The second area of concern is concrete that fails due to environmental effects. Freeze thaw damage and reinforcement corrosion are two common results.

Freeze thaw damage is caused by the formation of ice within the cement matrix, resulting in expansion damage to the concrete. Whether or not this formation of ice becomes a problem depends upon a combination of the permeability, water-to-cement ratio, air void spacing and size, total entrained air, and the extent of microcracking. The best indicator of concrete’s ability to avoid freeze thaw damage is successful completion of ASTM C666, Method A to 90% at 300 cycles. It is recommended that ASTM C666 testing be conducted at six-month intervals.

Corrosion damage is caused by infiltration of moisture and corrosive compounds into the hardened concrete, or excessive chlorides present in the plastic concrete mix. This moisture and compounds can attack metallic components within the tie. Limiting concrete permeability is the best way to protect against potential corrosion. Water-to-cement ratios (w/c) less than 0.4, proper concrete consolidation, admixtures (silica fume, high range water reducers, and flyash), and the fineness of the cement itself all contribute to adequate impermeability. Because of the prevalent use of high performance concrete (HPC) for the production of ties, corrosion is not generally a problem. Corrosion at the ends of prestressing tendons or exposed embedded components is not a problem for concrete ties. See Article 4.3.2.11.

4.2.3 DUGGAN CONCRETE EXPANSION TEST (1993)

a. The Duggan concrete core expansion test provides a relatively rapid measure of the potential for chemical expansion in concrete. The speed with which expansion occurs in nature depends upon the initial microcrack condition of the concrete, the availability of water, the availability of heat, the degree and frequency of loading stress, and the inherent chemistry of the cement-aggregate combination. Without externally loading the concrete, the Duggan test exaggerates and accelerates the heating/cooling and wetting/drying action of natural environment.

b. Five concrete cores of nominal 1 inch (25.4 mm) diameter are wet-drilled from any existing concrete or from proposed job mix concrete which has been cured in proposed fashion for a minimum of 7 days. The cores are end-faced with smooth parallel surfaces to a nominal length of 2 inches (51 mm). The five cores are then placed upright in a plastic container measuring roughly 3-1/2 inches (89 mm) diameter by 4 inches (102 mm) height, and are submerged under 1/2 inch (13 mm) cover with room temperature distilled water. A lid is placed on the container. The core treatment cycle is described below and depicted in Figure 30-4-2.

c. Treatment Cycle

• 72 hrs in water at 72 degrees F (22 degrees C).

• Measure core lengths (zero reading).

• 24 hrs dry heat at 180 degrees F (82 degrees C).





• Tolerances: Time ±1 hr.Figure 30-4-2. Duggan Core Treatment

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• Temperature ±1.5 degrees F (0.8 degrees C).

NOTE: After each dry oven heating, bench cool cores for 1 hr prior to placing back in water. Do not change the water during the treatment or during the subsequent expansion phase of this test.

d. The first core length measurements (zero reading) are taken at the end of the initial 3 day soaking period and prior to any hot oven drying. The reason for this is to include any natural physical expansion caused by water uptake at saturation but to exclude any unnatural chemical expansions that may subsequently occur in the cores. Following the final oven heating, the cores are allowed to bench cool for 1 hour and then are placed back in their room temperature distilled water (unchanged). This constitutes the starting point or Day Zero for the expansion test. Core length measurements should then be taken at days 1 and 3, and twice-weekly for the first three weeks. Length changes for the 5 cores should be averaged in terms of percent expansion. Measurements taken on cores drilled from existing bridge abutments ranging in age up to 80 years have indicated that expansion in the Duggan test should not exceed 0.05% at day 20 for durable crack-free concrete. Until more experience and data is obtained on North American concrete ties, the permissible core expansion at Day 20 should not exceed 0.15%.

4.2.4 METAL REINFORCEMENT (2003)

a. Strand for pretensioning tendons shall conform to ASTM A 416, “Specification for Uncoated Seven-Wire Stress-Relieved Strand for Prestressed Concrete,” or ASTM A 886, “Specification for Indented Seven-Wire Stress-Relieved Strand for Prestressed Concrete”.

Wires for pretensioning tendons shall conform to ASTM A 421, “Specification for Uncoated Stress-Relieved Wire for Prestressed Concrete” or ASTM A 881, “Specification for Steel Wire, Deformed, Stress-Relieved or Low-Relaxation for Prestressed Concrete Railroad Ties”.

b. Strands other than those listed in ASTM A 416 or A 886 and wires other than those listed in ASTM A 421 or A 881 may be used provided they conform to the requirements of these specifications and have no properties which make them less satisfactory than those listed in these specifications.

c. Steel bars for posttensioning tendons shall conform to ASTM A 722, “Specification for Uncoated High-Strength Steel for Prestressed Concrete”. Bars of other designations may be used provided they conform to the requirements for yield strength, tensile strength, and elongation, stipulated in ASTM A 722.

d. Reinforcing bars shall conform to one of the following specifications, except that yield strength shall correspond to that determined by tests on full-size bars; and for reinforcing bars with a specified yield strength of the reinforcing steel, fy ,exceeding 60,000 psi (414 MPa), fy , shall be the stress corresponding to a strain of 0.35%:

(1) “Specifications for Deformed Billet-Steel Bars for Concrete Reinforcement” (ASTM A 615).

(2) “Specifications for Rail-Steel Deformed Bars for Concrete Reinforcement” (ASTM A 616). If Bars meeting these specifications are to be bent, they shall also meet the bending requirements of ASTM A 615 for Grade 60.

(3) “Specifications for Axle-Steel Deformed Bars for Concrete Reinforcement” (ASTM A 617).

e. Plain bars for spiral reinforcement shall conform only to the strength requirements and minimum elongation of the appropriate specification prescribed in paragraph d.

f. Reinforcement to be welded shall be indicated on the drawings and the welding procedure to be used shall be specified. The ASTM specification shall be supplemented by requirements assuring satisfactory weldability by this procedure in conformity with “Recommended Practices for Welding Reinforcing Steel, Metal Inserts, and Connections in Reinforced Concrete Construction” (AWS D 12.1) The supplementary specification requirements shall be designated in the order, and conformance with requirements shall be confirmed by the supplier at the time of delivery.

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g. Bar and rod mats for concrete reinforcement shall be the clipped type conforming to “Specifications for Fabricated Steel Bar or Rod Mats Concrete Reinforcement” (ASTM A 184).

h. Plain wire for spiral reinforcement shall conform to “Specifications for Cold-Drawn Steel Wire for Concrete Reinforcement” (ASTM A 82), except that fy shall be the stress corresponding to a strain of 0.35% if the yield strength specified in the design exceeds 60 000 psi (414 MPa)

i. Welded plain wire fabric for concrete reinforcement shall conform to “Specifications for Welded Steel Wire Fabric for Concrete Reinforcement” (ASTM A 185), and to the stipulation of paragraph h regarding measurement of fy, except that welded intersections shall be spaced not farther apart than 12 inches (305 mm) in the direction of the principal reinforcement.

j. Deformed wire for concrete reinforcement shall conform to “Specifications for Deformed Steel Wire for Concrete Reinforcement” (ASTM A 496), except that wire shall not be smaller than size D-41 and that fy shall be the stress corresponding to a strain of 0.35% if the yield strength specified in the design exceeds 60,000 psi (414 MPa).

k. Welded deformed wire fabric for concrete reinforcement shall conform to “Specifications for Welded Deformed Steel Wire Fabric for Concrete Reinforcement” (ASTM A 947) and to the stipulation of paragraph j regarding measurement of fy, except that welded intersections shall be spaced not farther apart than 16 inches (406 mm) in the direction of the principal reinforcement.

l. Steel pipe or tubing for composite members shall conform to one following:

(1) Grade B, ASTM A 53.

(2) ASTM A 500.

(3) ASTM A 501.

(4) Grade specified by the manufacturer and supported by design and test data subject to the approval of the engineer.

m. Structural steel used in conjunction with reinforcing for composite members shall conform to one of the following:

(1) Steel used for tie bars of two block concrete ties shall provide double the corrosion resistance of 1018 steel as determined by ASTM Specification B-117. Corrosion protection systems such as painting or galvanizing, which may be abraded by sharp angular ballast particles, are not acceptable. Minimum thickness of the tie bar shall be 0.236 inch (6 mm).

(2) ASTM A 242.

(3) ASTM A 440.

(4) ASTM A 441.

(5) ASTM A 558.

(6) Grade specified by manufacturer and supported by design and test data subject to the approval of the engineer.

4.2.4.1 Reinforcement Placement and Spacing

The placement and spacing of reinforcement, prestressing steel and prestressing ducts shall be in accordance with applicable requirements of the AREMA Manual, Chapter 8, Concrete Structures and Foundations, Part 1, Materials, Tests and

1 Deformed wire is denoted by the letter “D”, followed by a number indicating the wire is cross sectional area in hundredths of a square inch thus, the minimum size permitted in this specification must have a cross sectional area of 0.04 square inches (26 mm2).

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Construction Requirements, Article 1.10.5. Spacing of Reinforcement, except that tolerances for placing shall meet the requirements of Article 4.3.2.12.

4.2.4.2 Supports

Reinforcement, prestressing steel, and ducts shall be accurately placed and adequately supported before concrete is placed and shall be secured against displacement within permitted tolerances. Welding of crossing bars shall not be permitted for assembly of reinforcement unless authorized by the engineer.

SECTION 4.3 TIE DIMENSIONS, CONFIGURATION AND WEIGHT

4.3.1 SPECIAL CONSIDERATIONS (1992)

4.3.1.1 Track Machinery Limitations

a. In addition to those considerations covered in Section 4.1, General Considerations, the following maximum dimensions will permit tamping with many present-day ballast tamping machines and will allow other related work to be handled in a mechanized manner:

(1) Tie width = 13 inches (330 mm).

(2) Tie depth = 10 inches (250 mm).

(3) Tie length = 9 -0 (2.740 m).

b. In order to prevent damage in handling or by tamper feet, the tie configuration shall be such that sharp angles or projections are avoided.

4.3.1.2 Weight

For ease of handling it is recommended that the weight of tie not exceed approximately 800 lb (363 kg).

4.3.2 REQUIREMENTS (2007)

4.3.2.1 Length

The overall nominal length of standard production prestressed concrete cross ties shall not exceed 9’-0” (2.740 m), exclusive of prestressing tendons. The nominal length shall not be less than 7’-9” (2.360 m) and 8’-0” (2.440 m) for post-tensioned and pretensioned concrete ties, respectively. A tolerance of +/- ¼ inch (6.35 mm) from nominal length is permitted.

The overall nominal length for specialty ties such as grade crossing ties and turnout ties may be other than the lengths allowedfor standard ties as approved by the Engineer.

4.3.2.2 Width

The minimum width of ballast bearing area of tie shall not be less than 8 inches (200 mm). Width of tie at top surface from railseat area to end of tie shall not be less than 6 inches (150 mm). The maximum width must not exceed 13 inches (330 mm). Tolerance of ±1/8 inch (3.18 mm) from nominal width is permitted.

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4.3.2.3 Minimum Depth

The minimum design depth of any section of tie shall not be less than 6 inches (150 mm). A manufacturing tolerance of +1/4 inch and –1/8 inch (+6.35 mm and –3.18 mm) is permitted from design depth.

4.3.2.4 Maximum Depth

Maximum design depth of any section of tie shall not be more than 10 inches (250 mm). A manufacturing tolerance of +1/4 and –1/8 inch (+6.35 mm and –3.18 mm) is permitted from design depth.

4.3.2.5 Track Gauge

The placement of the fastening system in concrete crossties is based on the fastener manufacturer’s recommendations and biased by the preferences of the customer. The issue is the distribution of clearances designed into the basic rail seat layout.Many fastenings are shown in recommended layouts with the clearance evenly divided between the field and gauge sides of the rail. Some customers prefer to have all clearance shown on the gauge side since revenue tonnage will ultimately close the clearance on the field side. Often the field to field shoulder spacing is reduced in the initial design to have zero clearance on the field side of the rail.

When concrete crossties are installed, tight gauge can arise even though the ties are manufactured according to a proper design. Concrete ties shall provide for 56.5 inch gauge +/- 0.0625" exclusive of rail tolerances. From Chapter 4, Rail, Table 4-2-2. Section Tolerances, it can be seen that the allowable variations in the rail can account for significantly greater track gauge variations.

Using an ideal rail section (no plus or minus tolerances) on a tie designed to provide perfect gauge will result in 56.5 inch gauge. Using the same tie with rail with maximum plus tolerances on the head (+0.025"), base (+0.040), and asymmetry (0.050) would provide tight gauge by 1/8". A rail with minimum tolerances would provide wide gauge by 1/8".

In addition, two situations can contribute to tight gauge independent of tie specifications or rail tolerances. The first situationoccurs with tie skewing, which can result when ties are not perpendicular to the rail. One half inch of skewing between tie ends on 8’-6" ties will reduce gauge by 0.065". The second situation is warpage in the plastic insulators can remove as much as 0.065" when the rails are not under load.

Fortunately, all of these situations (except for rail tolerances) will improve with tamping and traffic. Insulator warp will usually disappear with modest amounts of traffic.

4.3.2.6 Rail Cant

The rail seat shall provide for a cant of 1 in 40 ±5 toward center line of tie unless otherwise specified.

4.3.2.7 Rail Seat Plane

The rail seat shall be a flat smooth surface, ±1/32 inch (0.80 mm).

4.3.2.8 Differential Tilt of Rail Seats

A differential tilt in the direction of the rail of one rail seat to the other shall (on a width of 6 inches (152.4 mm)) not exceed 1/16 inch (1.6 mm).

4.3.2.9 Protrusion of Pretensioning Tendons

Strands or wires shall not project more than 1/4 inch (6.4 mm) beyond the ends of the ties, or as specified by the Engineer.

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4.3.2.10 End of Posttensioning Tendons

To protect against corrosion, the ends of posttensioning tendons shall not protrude beyond the ends of the ties and shall be covered to the extent specified in Article 4.3.2.11 with concrete, epoxy grout or other material approved by the engineer.

4.3.2.11 Concrete Coverage for Corrosion Protection of Reinforcement

The minimum concrete cover of reinforcement, prestressing tendons, ducts, or prestressing end fittings1 shall be as follows:

NOTE: Pretensioned, prestressed ties that have been tested after being in service for 40+ years in extreme environmental conditions show no evidence of corrosion to tendons inside the exterior surface of the tie. No evidence suggests that end treatment is necessary to protect pretensioned tendons.

4.3.2.12 Tolerances for Placing Reinforcement

a. Placement tolerance for reinforcing steel is important to ensure that flexural strength, minimum cover, and electrical requirements are achieved.

The tolerance for depth of placement for conventional reinforcing steel shall be +/- 1/8 inch (+/- 3.18 mm). The tolerance for placement of prestressing steel shall be +/- 1/8 inch (+/- 3.18 mm) vertical and +/- 1/4 inch (+/- 6.4 mm) horizontal. Greater tolerances are allowable, provided the Supplier can show that the tie has adequate flexural strength (with even distribution of tendons), minimum cover is not compromised, and there are no electrical shorts.

b. The tolerance for longitudinal location of bends in reinforcing bars shall be ±2 inches (50 mm).

c. The tolerance for the location of ends of reinforcing bars shall be ±1/2 inch (±13 mm).

4.3.2.13 Surface Finish

a. The top and side surfaces of the ties shall present a smooth, uniform appearance. A random scattering of surface voids will not be cause for rejection. Heavy concentrations of surface voids or evidence of improper mixing, vibrating or curing will be cause for rejection.

b. Occasional spalling of a small portion of rail seat shoulders may occur during the stripping operation. Such spalling will not be cause for rejection unless it involves that portion of a shoulder against which the heel of rail fastening clip bears.

c. Concrete ties or cast in components shall be marked with indented or raised letters or numerals to identify the manufacturer, type of tie, form and cavity, year of manufacture, and date code as approved by the engineer. If ties are intended for use with grade crossing panels, only indented letters or numerals shall be allowed for those areas to be in contact with panels.

Reinforcement when used in Pre-tensioned or Post-tensioned cross ties: 3/4 in. (19 mm)Reinforcement when used in other cross ties: Comply with ACI 318

Specifications

1 This does not apply to the ends of pretensioning tendons which may protrude from the end of the tie. See also Article 4.3.2.9.

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SECTION 4.4 FLEXURAL STRENGTH OF PRESTRESSED MONOBLOCK TIES

4.4.1 FLEXURAL PERFORMANCE REQUIREMENTS FOR PRESTRESSED MONOBLOCK DESIGNS (2014)

4.4.1.1 Bending Moments

a. Figure 30-4-3 gives the unfactored positive bending moment at the centerline of the rail seat for tie lengths of 7 -9 , 8 -0 , 8 -6 and 9 -0 (2.360, 2.440, 2.590 and 2.740 m) for various tie spacings.

b. Bending moments may be interpolated for other tie lengths.

c. Requirements for factored design flexural values are obtained by the method described in Article 4.4.1.2.

4.4.1.2 Factored Design Flexural Values for Freight and Commuter Rail Systems

a. In consideration of the influence of speed and annual tonnage on tie design, the factored design flexural capacity may be determined from:

M = B.V.T.

where:

b. The use of strain attenuating tie pads in the rail fastening system has been shown to reduce positive bending moments. The factored design flexural capacity value, M, may, therefore, be reduced at the option of the engineer.

c. Factored design rail seat negative, tie center negative and tie center positive bending moments may be calculated from the factored design positive bending moment M, using the factors found in Table 30-4-1 and interpolating if necessary.

d. For tie designs having a reduced bottom width at the center of the tie, the positive moment at the rail seat will increase and the negative moment at the tie center will decrease when compared with a tie with a uniform bottom width, for a given ballast pressure.

M = the factored design positive bending moment at the center of the rail seatB = the bending moment in inch kips (kN-m) taken from Figure 30-4-3. For a particular tie length and spacingV = is the speed factor obtained from Figure 30-4-4T = the tonnage factor obtained from Figure 30-4-4

Table 30-4-1. Bending Moment Calculations

Tie Length Rail Seat Negative

CenterNegative

CenterPositive

7 -9 (2.360 m) 0.72M 1.13M 0.61M8 -0 (2.440 m) 0.64M 0.92M 0.56M8 -3 (2.520 m) 0.58M 0.77M 0.51M8 -6 (2.590 m) 0.53M 0.67M 0.47M9 -0 (2.740 m) 0.46M 0.57M 0.40M

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Figure 30-4-3. Unfactored Bending Moment at Centerline of Rail Seat

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Figure 30-4-4. Tonnage and Speed Factors

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e. In view of this condition, the rail seat and center positive flexural requirements and the negative center flexural requirements shall be modified accordingly. Required moment calculations are to be based on the geometry of the bottom surface of the tie subjected to uniform ballast pressure.

f. In lieu of moments based on calculations, the rail seat and center positive flexural requirements shall be increased by 10% and the center negative flexural requirements shall be decreased by 10%.

4.4.1.3 Factored Design Flexural Values for Light Rail Transit Systems

Light rail transit is a type of urban passenger transportation service that is not shared with freight or commuter passenger trains. It is further assumed that the wheel maintenance on light rail systems is better managed than is typically observed forfreight and commuter systems. Light rail transit vehicles typically have much lower axle weights than freight and commuter. Flexural design for transit loading can therefore be optimized for these less demanding conditions.

For axle weights under 35,000 lbf, calculate the required RS+ design load using Figure 30-4-3 using tie length and tie spacing. The factored design flexural capacity may be determined from:

M = B A V

where:

M = the factored design positive bending moment at the center of the rail seat

B = the bending moment in inch kips (kN-m) taken from Figure 30-4-3 for a particular tie length and spacing

A = Transit axle load reduction factor, determined by taking the design axle load divided by 82,000 lbf. When specifying or designing, construction and maintenance equipment loads should also be considered when determining the design axle load, as they may govern the design.

V = the speed factor obtained from Figure 30-4-4, but not less than 1.0

Note: Care must be taken during track construction to ensure ties are not center bound, potentially causing center cracking.

4.4.2 DESIGN CONSIDERATIONS (1988)

a. As well as satisfying the criteria in Article 4.4.1, prestressed concrete monoblock ties must also comply with other criteria which accord with good design practice as laid down in ACI Code 318.

b. It is recommended that the maximum precompression after all losses at any point in the cross ties should not exceed 2,500 psi (17.2 MPa).

c. Furthermore, there should be a minimum pre-compressive stress at any vertical cross section through the rail seat area of 500 psi (3.5 MPa) after all losses and without any applied load.

4.4.3 TEST REQUIREMENTS FOR APPROVING THE DESIGN OF A MONOBLOCK TIE (1988)

a. The minimum negative and positive flexural capacity at the rail seats of the tie shall be as shown in Article 4.4.1 for the tie length and spacing to be used when tested in accordance with the Rail Seat Vertical Load Test described in Article 4.9.1.4.

b. The minimum negative flexural capacity at the center of the tie shall be as shown in Article 4.4.1 for the tie length and spacing to be used when tested in accordance with the Negative Bending Moment Test described in Article 4.9.1.6.

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c. The minimum positive flexural capacity at the center of the tie shall be as shown in Article 4.4.1 for the tie length and spacing to be used when tested in accordance with the Positive Bending Moment Test described in Article 4.9.1.7.

d. The tie must meet the requirements of the Rail Seat Repeated-Load Test described in Article .

e. The tie must meet the requirements of the Bond Development or Tendon Anchorage Test described in Article 4.9.1.8.

SECTION 4.5 FLEXURAL STRENGTH OF TWO-BLOCK TIES

4.5.1 FLEXURAL PERFORMANCE REQUIREMENTS FOR TWO-BLOCK DESIGNS (1988)

a. Figure 30-4-5 gives the unfactored positive bending moment at the center line of the rail seat for tie block lengths of 30 inches, 33 inches and 36 inches (762 mm, 838 mm, 914 mm) for various tie spacings for Reinforced Two-Block Ties. Bending moments may be interpolated for other tie block lengths. Requirements for factored design flexural values are obtained by the method described in Article 4.4.1.2.

b. Figure 30-4-6 gives the unfactored positive bending moment at the centerline of the rail seat for the block lengths of 30 inches, 33 inches, 36 inches (76 cm, 84 cm, 91 cm) for various tie spacings, for Prestressed Two-Block Ties. Bending moments may be interpolated for other tie block designs.

c. For two-block reinforced and two-block prestressed ties, negative bending moments may be calculated from the calculated from the calculated rail seat positive bending moment, M as shown in Table 30-4-2.

4.5.1.1 Allowable Cracking

a. Reinforced cross ties when subjected to loads producing flexure in the blocks must crack in order for the main reinforcement to work. Corrosion of steel reinforcement is related to crack width and external environment. The maximum crack width allowed in Table 30-4-3, should not contribute to corrosion of steel reinforcement under normal railroad environments.

b. Cracks shall be measured on the surfaces of the tie block at a level directly opposite the reinforcement closest to the tension face of the tie. If it is not possible to measure a crack at this level due to chipping of the concrete or surface imperfections, measurements shall be taken equidistant above and below this level and the two values averaged to obtain the width of the crack.

c. Cracks shall be measured using a hand-held graduated microscope of sufficient power and accuracy to measure crack widths to the nearest. 0.001 inch (0.025 mm)

d. Cracks shall not extend to prestressing tendons or longitudinal reinforcing steel of less than 3/8 inch (9.352 mm) diameter.

Table 30-4-2. Negative Bending Moments

Tie Block Length Rail Seat Negative30 in. (760 mm) 0.72M33 in. (840 mm) 0.71M36 in. (910 mm) 0.70M

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e. Maximum and average crack widths shall not exceed those values shown in Table 30-4-3.

4.5.2 TEST REQUIREMENTS FOR APPROVING THE DESIGN OF A TWO-BLOCK TIE (1993)

a. The minimum positive flexural capacity of the tie blocks shall be as shown in Article 4.5.1 for the tie block length and tie spacing to be used when tested in accordance with the Rail Seat Positive and Rail Seat Negative Moment Tests described in Article 4.10.1.4 and Article 4.10.1.5.

b. The ties must meet the requirements of the Rail Seat Ultimate Load Test described in Article 4.10.1.9.

c. The ties must meet the requirements of the Rail Seat Repeated Load Test described in Article 4.10.1.8.

d. The ties must meet the requirements of the Center Negative and Center Positive Bending Moment Tests described in Article 4.10.1.6 and Article 4.10.1.7.

SECTION 4.6 LONGITUDINAL RAIL RESTRAINT


a. Fastenings for concrete ties must have the ability to restrain 2.4 kips (10.7 kN) per tie per rail longitudinal movement of rail as determined by test procedure specified in Article 4.9.1.12.

b. Welded rail must be laid at the proper temperature range or additional anchorage provided at the ends of strings.

SECTION 4.7 LATERAL RAIL RESTRAINT

4.7.1 RAIL FASTENING REQUIREMENTS (2015)

a. Track constructed of concrete ties and appropriate fasteners shall not experience gage widening of more than 1/4 inch (6.35 mm) under test conditions. (See Article 4.9.1.13 for design tests).

b. If a concrete shoulder is used to restrain lateral loads and lateral movement of the rail, a suitable bearing surface shall be provided to transmit the lateral forces to the tie.

c. Inserts shall be arranged to distribute the load uniformly in the body of the tie and through the rail bearing area. The railsupport insert shall withstand a pullout force of 12 kips (53.4 kN) (See Article 4.9.1.9, Article 4.9.1.10 and Article 4.9.1.13 for design tests).

Table 30-4-3. Allowable Crack Widths

Number of Cracks (Note 1) Maximum Width – Inch (mm) Average Width – Inch (mm)1 0.006 (0.153 mm) –2 0.006 (0.153 mm) 0.005 (0.127 mm)3 0.006 (0.153 mm) 0.004 (0.101 mm)4 or more 0.006 (0.153 mm) 0.003 (0.076 mm)

Note 1: Per side per tie block

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Figure 30-4-5. Bending Moment – Reinforced Two-Block Ties

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Figure 30-4-6. Bending Moment – Prestressed Two-Block Ties

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SECTION 4.8 ELECTRICAL PROPERTIES


Individual concrete cross ties for use in signal circuit tracks together with their fastenings should be electrically isolated fromthe running rails so as to provide a minimum impedance of 20,000 ohms per tie when a-c energy of 10 volts, 60 Hertz is applied (see Article 4.9.1.14 for test procedure).

SECTION 4.9 TESTING OF MONOBLOCK TIES

4.9.1 DESIGN TEST OF MONOBLOCK TIES (2014)

a. Prior to approval of concrete tie designs, monoblock concrete ties of the design under study shall be subjected to testing for compliance with these specifications. The tests specified herein shall be performed at testing facilities approved by the engineer.

b. Concrete ties and rail fastening systems shall be subjected to the specified acceptance tests. Failure of the concrete ties and rail fastenings to pass the prescribed tests will be cause for rejection. Existing concrete tie and fastening designs which have already passed tests equivalent to those specified herein may be accepted without additional testing as determined by the Engineer. For such acceptance to be given, certified laboratory test reports shall be submitted in sufficient detail as required by the Engineer in order to make the determination as to equivalency.

c. From a lot of not less than ten ties produced in accordance with these specifications, four ties will be selected at random by the engineer for laboratory testing. For design testing of fastenings, the manufacturer shall also furnish a section of tie or a concrete block with rail seat and rail fastening system identical to the concrete ties furnished for testing.

d. The tie block and each of four ties submitted for testing shall be carefully measured and examined to determine their compliance with the requirements of Section 4.2, Material and Section 4.3, Tie Dimensions, Configuration and Weight.Upon satisfactory completion of this examination, the tie block and two ties, which shall be known and identified as Tie “1” and “2”, shall be subjected to performance tests specified in Article 4.9.1.4, Article , Article 4.9.1.6,Article 4.9.1.7, Article 4.9.1.8, Article 4.9.1.9, Article 4.9.1.10, Article 4.9.1.10, Article 4.9.1.12, Article 4.9.1.13, and Article 4.9.1.14. The remaining two ties, which will be known and identified as Ties “3” and “4”, will be retained by the engineer for further test use and as a control for dimensional tolerances and surface appearance of ties subsequently manufactured.

4.9.1.1 Sequence of Design Tests (Tie “1”)

The sequence of design performance tests using Tie “1” shall be as follows:

a. Rail Seat Vertical Load Test (described in Article 4.9.1.4). Shall be performed on one rail seat, hereinafter designated rail seat A.

b. Center Negative Bending Moment Test (described in Article 4.9.1.6).

c. Center Positive Bending Moment Test (described in Article 4.9.1.7).

d. Rail Seat Vertical Load Test (described in Article 4.9.1.4). Shall be performed on the other rail seat, hereinafter designated rail seat B.

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e. Rail Seat Repeated Load Test (described in Article ). Shall be performed on rail seat B.

f. Bond Development, Tendon Anchorage, and Ultimate Load Test (described in Article 4.9.1.8). Shall be performed on rail seat A.

4.9.1.2 Sequence of Design Tests (Tie “2”)

The sequence of design performance tests using Tie “2” shall be as follows:

a. Fastening Insert Test (described in Article 4.9.1.9). Shall be performed on all inserts.

b. Fastening Uplift Test (described in Article 4.9.1.10). Shall be performed on one rail seat.

c. Electrical Resistance and Impedance Test (described in Article 4.9.1.14).

4.9.1.3 Sequence of Design Tests (Tie Block)

The sequence of design performance tests using the tie block shall be as follows:

a. Tie Pad Test1 (described in Article 4.9.1.15).

b. Fastening Uplift Test Part A (described in Article 4.9.1.10).

c. Fastening Longitudinal Restraint test (described in Article 4.9.1.12).

d. Fastening Repeated load Test (described in Article 4.9.1.10).

e. Fastening Longitudinal Restraint Test (described in Article 4.9.1.12).

f. Fastening Uplift Test Part A (described in Article 4.9.1.10).

g. Fastening Lateral Restraint Test (described in Article 4.9.1.13).

h. Tie Pad Test (described in Article 4.9.1.15).

4.9.1.4 Rail Seat Vertical Load Test

With the tie supported and loaded as shown in Figure 30-4-7 apply the load continuously and without shock until the load (P) required to produce the specified railseat negative moment from Section 4.4, Flexural Strength of Prestressed Monoblock Tiesis obtained. This load shall be held for not less than 3 minutes, during which time an inspection shall be made to determine ifstructural cracking occurs. In like manner, the tie shall be supported and loaded as shown in Figure 30-4-8 to produce the Section 4.4 required rail seat positive moment. An illuminated 5-power magnifying glass shall be used to locate cracks. If structural cracking does not occur, the requirements of each portion of this test will have been met. Other material may be substituted for the rubber supports shown, by agreement with the Engineer.

4.9.1.5 Rail Seat Repeated-Load Test

a. Following the vertical load test for positive moment on rail seat B, the load shall be increased at rate of at least 5 kips (22 kN) per minute until the tie is cracked from its bottom surface up to the level of the lower layer of reinforcement. This load shall be recorded as the cracking load. Cracking load is shown in Figure 30-4-9.

1 Test shall be conducted on three pads. The two pads providing highest and lowest spring rate values shall be discarded and remaining pad shall be used for tests Article 4.9.1.3b through h.

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Figure 30-4-7. Rail Seat Negative Moment Test

M = NEGATIVE MOMENT AT THE RAIL SEAT AS REQUIRED IN ARTICLE 4.4.1 OR ARTICLE 4.5.1

- 3" (or 76 mm)

M = POSITIVE MOMENT AT THE RAIL SEAT AS REQUIRED IN ARTICLE 4.4.1 FOR PRESTRESSED MONOBLOCK TIES OR ARTICLE 4.5.1 FOR TWO BLOCK TIES

- 2.25" (or 57 mm)

Figure 30-4-8. Rail Seat Positive Moment Test

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b. After removal of the static rail seat load necessary to produce cracking, and substitution of 1/4 inch (6.35 mm) -thick plywood strips for those in Figure 30-4-8, the tie shall be subjected to 3 million cycles of repeated loading with each cycle varying uniformly from 4 kips (17.8 kN) to the value of 1.1P. The repeated loading shall not exceed 600 cycles per minute. If, after the application of the total 3 million cycles, the tie can support a rail seat load of 1.5P for 3 minuteswithout tendon slip of more than 0.001 inch (0.025 mm), concrete compressive failure, concrete shear cracks, or tendon failure, then the requirements of this test will have been met. This 3 million cyle repeated load testing requirement may be waived for proven designs with satisfactory in-track performance.

4.9.1.6 Center Negative Bending Moment Test

With the tie supported and loaded as shown in Figure 30-4-10 a load increasing at a rate not greater than 5 kips (22kN) per minute shall be applied until the load required to produce the specified negative center design moment from Table 30-4-3 is obtained. The load shall be held for not less than 3 minutes, during which time an inspection shall be made to determine if structural cracking occurs. An illuminated, 5-power magnifying glass may be used to locate cracks. If structural cracking does not occur the requirements of this test will have been met.

4.9.1.7 Center Positive Bending Moment Test

With the tie supported and loaded as shown in Figure 30-4-11, a load increasing at a rate not greater than 5 kips (22 kN) per minute shall be applied until the load required to produce the specified positive center design moment from Table 30-4-3 is obtained. The load shall be held for not less than 3 minutes during which time an inspection shall be made to determine if structural cracking occurs. An illuminated, 5-power magnifying glass may be used to locate cracks. If structural cracking does not occur, the requirements of this test will have been met.

4.9.1.8 Bond Development, Tendon Anchorage, and Ultimate Load Test

a. Pretensioned concrete ties shall be tested for bond development, and ultimate strength as specified below:

(1) With the tie supported and loaded at rail seat A as shown in Figure 30-4-8, apply a total load of 1.5P (the load P shall be as determined in “Rail Seat Vertical Load Test” for positive moment) and hold this load for a period not less than 3 minutes.

Figure 30-4-9. Cracking Load

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(2) If there is no more than 0.001 inch (0.025 mm) tendon slippage determined by an extensometer reading to 1/10,000 of an inch (1/400 mm), the requirements of this test will have been met. The measurement shall be made on the outermost tendons of the lower layer. The load shall then be increased at not greater than 10 kips per minute (44 kN/min) until failure occurs while continuing to measure for tendon slippage. The load at which tendon slippage occurs, the maximum load obtained, and the root failure mode at maximum load shall be documented as either tendon slip, tendon breakage, or concrete compressive failure.

b. Post-tensioned concrete ties shall be tested for tendon anchorage and ultimate strength as specified below:

With the tie supported and loaded as shown in Figure 30-4-8, a load increasing at a rate not greater than 5 kips (22 kN) per minute shall be applied until a total load equal to 1.5P is obtained. If the tie can support this load for a period of 5 minutes, the requirements of this test will have been met. The load shall then be increased until ultimate failure of the tie occurs, and the maximum load obtained shall be recorded.

4.9.1.9 Fastening Insert Test

Fastening inserts shall be subjected to a pull-out test and a torque test as follows:

a. The pull-out test shall be performed on each insert as shown on Figure 30-4-12. An axial load of 12 kips (53.4 kN) shall be applied to each insert separately and held for not less than 3 minutes, during which time an inspection shall be made to determine if there is any slippage of the insert or any cracking of the concrete.

NOTE: Mortar cracking in the vicinity of the insert is not a cause for failure. If failures occur, then the requirements of this test will not have been met. Inability of the insert itself to resist the 12 kips (53.4 kN) load without permanent deformation shall also constitute failure of this test.

M = NEGATIVE MOMENT AT THE CENTER OF THE TIE AS REQUIRED IN ARTICLE 4.4.1

Figure 30-4-10. Tie Center Negative Moment Test

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b. Following successful completion of the insert pull-out test, the torque test shall be performed on each insert. A torque of 250 ft-lb (339 N•m) shall be applied about the vertical axis of the insert by means of a calibrated torque wrench and

M = POSITIVE MOMENT AT THE CENTER OF THE TIE AS REQUIRED IN ARTICLE 4.4.1

Figure 30-4-11. Tie Center Positive Moment Test

Figure 30-4-12. Insert Pullout Test

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a suitable attachment to the insert. The torque shall be held for not less than 3 minutes. Ability of the insert to resist thistorque without rotation, cracking of the concrete, or permanent deformation shall constitute passage of this test.

4.9.1.10 Fastener Uplift Test (See Part 2, Evaluative Tests for Tie Systems, 2.6.1, Test 5A: Fastener Uplift (2014))

4.9.1.11 Fastening Repeated-Load Test

Refer to Chapter 30, Part 2, Evaluative Tests for Tie Systems, Test 5C for details.

4.9.1.12 Fastener Longitudinal Restraint Test

Refer to Chapter 30, Part 2, Evaluative Tests for Tie Systems, Test 5B for details.

4.9.1.13 Fastener Lateral Load Restraint Test

Refer to Chapter 30, Part 2, Evaluative Tests for Tie Systems, Test 5D for details.

4.9.1.14 Fastener Electrical Impedance Test

Refer to Chapter 30, Part 2, Evaluative Tests for Tie Systems, Test 7 for details.

4.9.1.15 Tie Pad Test

Refer to Chapter 30, Part 2, Evaluative Tests for Tie Systems, Test 4A for details.

The requirements of this test will have been met, if

a. Pad returns to within 0.002 inch (0.051 mm) of its original position 10 seconds after load removal.

b. Spring rate values determined from both pad tests, conducted as part of the design performance tests specified in Article 4.9.1.3, do not vary by more than 25%.

c. Spring rate values determined from initial tests in Article 4.9.1.3a conducted on the three test pads, as part of the design performance tests specified do not vary by more than 25%.

d. Spring rate values determined from final tests in Article 4.9.1.3h conducted on the two test pads, as part of the design performance tests specified do not vary by more than 25%.

4.9.1.16 Tie Pad Attenuation Test

Refer to Chapter 30, Part 2, Evaluative Tests for Tie Systems, Test 4B for details.

4.9.1.17 Wear/Abrasion Test


4.9.1.18 Single Tie Lateral Push Test


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4.9.2 PRODUCTION QUALITY CONTROL OF MONOBLOCK TIES (1993)

After tie and rail fastening system have passed the tests in Article 4.9.1 and have been approved by the engineer, further production of these items may proceed without further design testing. During production of such an approved design, quality-control tests must be performed to assure a uniform, high-quality product.

4.9.2.1 Daily Production Quality-Control Tests

The following production quality-control tests shall be performed prior to delivery on one tie selected at random from every 200 ties or fraction thereof produced each day.

a. The rail seat configuration and inset location shall be verified for compliance with the requirements of Article 4.3.2.

b. The Rail Seat Vertical Positive Load Test, Article 4.9.1.4, shall be performed. The load shall be applied at a rate of least 5 kips (22 kN) per minute and be held for at least 1 minute.

c. The Fastening Insert Test, Article 4.9.1.9, shall be performed on all inserts per tie when the instant demolding process is used.

4.9.2.2 Additional Quality-Control Tests

To assure the production of cross ties and rail fastenings which comply with these specifications, the manufacturer shall institute whatever additional quality-control tests, including concrete compressive strength tests (see Article 4.2.2), deemed necessary.

4.9.2.3 Failure to Pass Production Quality-Control Tests

Should any test tie fail the tests required by Article 4.9.2.1, two additional ties from that same 200-tie lot shall be tested. In the event either of these ties fails, 100% of the remainder of the 200-tie lot shall be either tested or rejected.

4.9.2.4 Disposition of Test Ties

A tie cracked (not structurally under Definition 19) and otherwise undamaged after testing, will be considered acceptable for use in track unless non-structural cracks are specifically rejected by the engineer prior to testing.

4.9.2.5 Bond Development or Tendon Anchorage Quality-Control Test

One tie selected at random from every 2,000 ties produced shall be subjected to the Bond Development or Tendon Anchorage Test described in Article 4.9.1.8. A load rate exceeding 5 kips (22.25 kN) per minute may be applied. If the tie does not meet the requirements of Article 4.9.1.8 three additional ties shall be tested, and if any of the three ties do not meet the requirements of Article 4.9.1.8, the entire lot may be rejected at the option of the engineer.

4.9.2.6 Location for Inspection and Quality-Control Testing

Quality-control testing of production ties may be performed at any test facility, including such facilities at the manufacturer’s plant, provided they meet the approval of the engineer. Testing may be observed by the engineer or his designated representative if he so elects. Two copies of the results of all such tests shall be submitted to the engineer within 7 days of the performance of the tests.

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SECTION 4.10 TESTING OF TWO-BLOCK TIES

4.10.1 DESIGN TESTS OF TWO-BLOCK TIES (2006)

a. Prior to approval of two-block tie designs, concrete ties of the design under study shall be subjected to testing for compliance with these specifications. The tests specified herein shall be performed at testing facilities approved by the engineer within 30 days of casting.

b. Concrete ties and rail fastening systems shall be subjected to the specified acceptance tests. Failure of the concrete ties and rail fastenings to pass the prescribed tests will be cause for rejection. Existing concrete tie and fastening designs which have already passed tests equivalent to those specified herein may be accepted without additional testing as determined by the Engineer. For such acceptance to be given, certified laboratory test reports shall be submitted in sufficient detail as required by the Engineer in order to make the determination as to equivalency.

c. From a lot of not less than ten ties produced in accordance with these specifications four ties will be selected at random by the engineer for laboratory testing. For design testing of fasteners the manufacturer shall also furnish a section of the tie or a concrete block with rail seat and rail fastening system identical to the concrete ties furnished for testing.

d. The tie block and each of the four ties submitted for testing shall be carefully measured and examined to determine their compliance with the requirements of Section 4.2, Material and Section 4.3, Tie Dimensions, Configuration and Weight. Upon satisfactory completion of this examination, the tie block and the two ties, which shall be known and identified as Ties “1” and “2”, shall be submitted to performance tests. The remaining two ties, which will be known and identified as Ties “3” and “4”, will be retained for further use and as a control for dimensional tolerance and surface appearances of ties subsequently manufactured.

4.10.1.1 Sequence of Tests (Tie “1”)

The sequence of design tests performed with Tie “1” shall be as follows:

a. Rail Seat Positive Moment Test (described in Article 4.10.1.4) shall be performed on each rail seat.

b. Rail Seat Negative Moment Test (described in Article 4.10.1.5) shall be performed on each rail seat.

c. Center Negative Bending Moment Test (described in Article 4.10.1.6).

d. Rail Seat Repeated Load Test (described in Article 4.10.1.8).

e. Rail Seat Ultimate Load Test (described in Article 4.10.1.9).

4.10.1.2 Sequence of Tests (Tie “2”)

The sequence of design tests performed with Tie “2” shall be as follows:

a. Center Positive Bending Moment Test (described in Article 4.10.1.7).

b. Fastening Insert Test (described in Article 4.10.1.10) shall be performed on all inserts.

c. Fastening Uplift Test (described in Article 4.10.1.11) shall be performed on one rail seat.

d. Electrical Impedance Test (described in Article 4.10.1.14).

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4.10.1.3 Sequence of Tests (Tie Block)

The sequence of design performance tests using tie block shall be as follows:

a. Tie Pad Test1 (described in Article 4.10.1.6).

b. Fastening Uplift Test Part A (described in Article 4.10.1.11).

c. Fastening Longitudinal Restraint Test (described in Article 4.10.1.13).

d. Fastening Repeated Load Test (described in Article 4.10.1.12).

e. Fastening Longitudinal Restraint Test (described in Article 4.10.1.13).

f. Fastening Uplift Test Part A (described in Article 4.10.1.11).

g. Fastening Lateral Restraint Test (described in Article 4.10.1.14).

h. Tie Pad Test (described in Article 4.10.1.16).

4.10.1.4 Rail Seat Positive Bending Moment Test

a. With tie supported and loaded as shown in Figure 30-4-8, a load increasing at a rate not greater than 5 kips (22 kN) per minute shall be applied until the load (P) required to produce the specified rail seat design positive moment from Article 4.5.1b, is obtained.

b. This load shall be held for not less than 3 minutes, during which time an inspection shall be made to determine if structural cracking occurs. An illuminated 5-power magnifying glass may be used to locate cracks. If structural cracking does not occur or (in the case of reinforced partially prestressed ties) crack widths do not exceed the widths specified in Article 4.5.1.1e, the requirements of this test will have been met.

4.10.1.5 Rail Seat Negative Bending Moment Test

With tie supported and loaded as shown in Figure 30-4-7, a load increasing at a rate not greater than 5 kips (22 kN) per minute shall be applied until the load (P) required to produce the specified rail seat design negative moment from Article 4.5.1, is obtained. This load shall be held for not less than 3 minutes, during which time an inspection shall be made to determine if structural cracking occurs. If structural cracking does not occur, or (in the case of reinforced or partially prestressed ties) crack widths do not exceed the widths specified in Article 4.5.1.1e, The requirements of this test will have been met.

4.10.1.6 Center Negative Bending Moment Test

With Tie 1 supported and loaded as shown in Figure 30-4-13, a load increasing at a rate not greater than 5 kips (22 kN) per minute shall be applied until a load of 11 kips (49 kN) causing a moment of 55 inch-kips (6.2 kN-m) has been reached. If structural cracking does not occur on the gage faces of the blocks and the deflection at the center of the tie does not exceed 0.5 inch (12.8 mm), the requirements of this test will have been met. Continue loading at thesame rate until a load of 19 kips (84.5 kN) causing a moment of 95 inch-kips (10.7 kN-m) is reached and is held for five minutes. If structural cracking does not occur on the gage faces of the blocks and the permanent deformation of the tie bar recorded one minute after load removal is less than 1/4 inch (6.35 mm), the requirements of this test will have been met.

1 Test shall be conducted on three pads. The two pads providing highest and lowest spring rate values shall be used for tests Article 4.9.1.3b through h.

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4.10.1.7 Center Positive Bending Moment Test

With Tie 2 supported and loaded as shown in Figure 30-4-14, a load increasing at a rate not greater than 5 kips (22 kN) per minute shall be applied until a load of 11 kips (49 kN) causing a moment of 55 inch-kips (6.2 kN-m) has been reached. If structural cracking does not occur on the gage faces of the blocks and the deflection at the center of the tie does not exceed 0.5inch (12.8 mm), the requirements of this test will have been met. Continue loading at the same rate until a load of 19 kips (84.5kN) causing a moment of 95 inch-kips (10.7 kN-m) is reached and is held for five minutes. If structural cracking does not occur on the gage faces of the blocks and the permanent deformation of the tie bar recorded one minute after load removal is less than 1/4 inch (6.35 mm), the requirements of this test will have been met.

4.10.1.8 Rail Seat Repeated-Load Test

With the tie supported and loaded as shown in Figure 30-4-8, except that 1/4 inch (6.35 mm) -thick plywood strips shall be substituted for the pads, one rail seat of the ties shall be subjected to 3 million cycles of repeated loading with each cycle varying uniformly from 4 kips (17.8 kN) to the value (1.1P) required to produce the specified rail seat positive bending moment from Article 4.5.1. If after 3 million cycles, the tie can support the rail seat load (1.1P), the requirements of this test will have been met.

4.10.1.9 Rail Seat Overload and Ultimate Load Test

With the tie supported and the other rail seat loaded as shown in Figure 30-4-8, a load increasing at a rate not greater than 5 kips (22 kN) per minute shall be applied until a total load of 1.75P is obtained. If the tie can support this load for a period of not less than 5 minutes, the requirements of this test will have been met. The load shall then be increased until ultimate failureof the tie occurs, and the maximum load obtained shall be recorded.

4.10.1.10 Fastening Insert Test

The test procedure specified in Article 4.9.1.9 shall be used to determine the acceptability of inserts.

Figure 30-4-13. Two Block Tie Center Negative Bending Test

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4.10.1.11 Fastening Uplift Test

The Fastening Uplift Test shall be performed in two parts as specified in Article 4.9.1.10.

4.10.1.12 Fastening Repeated-Load Test

The Fastening Repeated - Load Test shall be performed following the test procedure specified in Article 4.9.1.10.

4.10.1.13 Fastening Longitudinal Restraint Test

Both before and after the performance of the Fastening Repeated Load Test and without disturbing the rail fastening assembly in any manner other than retorquing anchor bolts, the tie and fastening shall be subjected to a Longitudinal Restraint Test following the test procedure specified in Article 4.9.1.12.

4.10.1.14 Fastening Lateral Restraint Test

The tie and fastening shall be tested for lateral restraint following the test procedure specified in Article 4.9.1.13.

4.10.1.15 Electrical Impedance Test

The tie and fastening shall be tested for electrical conductivity following the test procedure specified in Article 4.9.1.14.

4.10.1.16 Tie Pad Test

The Tie Pad Test shall be performed following the test procedure specified in Article 4.9.1.15.

Figure 30-4-14. Two Block Tie Center Positive Bending Test

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4.10.2 PRODUCTION QUALITY CONTROL OF TWO-BLOCK TIES (1988)

After a tie and rail fastening system have passed the tests in Article 4.10.1 and have been approved by the engineer, further production of these items may proceed without further design testing. During production of such an approved design, quality-control tests must be performed to assure a uniform high-quality product.

4.10.2.1 Daily Production Quality-Control Tests

The following production quality-control tests shall be performed prior to delivery and within 30 days of manufacture of one tie selected at random from every 200 ties or fraction thereof produced each day.

a. The distance from center of the tie to the center of the rail seats shall be verified and by use of a template, the rail seatconfiguration (including shoulders and inserts if they are used) shall be verified for compliance with the requirements of Article 4.3.2.

b. The Rail Seat Positive Moment Test, Article 4.10.1.4, shall be performed.

c. The Fastener Insert, Article 4.9.1.9, shall be performed.

4.10.2.2 Additional Quality-Control Tests

To assure the production of cross ties and rail fastenings which comply with these specifications, the manufacturer shall institute whatever additional quality-control test, including concrete compressive strength tests (see Article 4.2.2.1), deemed necessary.

4.10.2.3 Failure to Pass Production Quality-Control Tests

Should any test tie fail the tests required by Article 4.10.2.1 above, two additional ties from that same 200-tie lot shall be tested. In the event either of these ties fails, 100% of the remainder of the 200-tie lot shall be either tested or rejected.

4.10.2.4 Disposition of Test Ties

Ties that pass the testing requirements and are not cracked or otherwise damaged after testing will be considered acceptable foruse in track.

4.10.2.5 Rail Seat Overload Quality-Control Test

One tie selected at random from every 2,000 ties produced shall be subjected to the Rail Seat Overload Load Test described in Article 4.10.1.9 If the tie does not meet the requirements of Article 4.10.1.9, three additional ties shall be selected at random and tested. If any of the three additional ties do not meet the requirements of Article 4.10.1.9 the entire lot may be rejected at the option of the engineer.

4.10.2.6 Location for Inspection and Quality-Control Testing

Quality-control testing and inspection of production ties may be performed at any test facility, including such facilities at themanufacturer’s plant, provided they meet the approval of the engineer. The engineer shall be notified in advance of dates scheduled for quality-control tests. Testing may be observed by the engineer or his designated representative if he so elects. Two copies of all such tests shall be submitted to the engineer within 7 days of the performance of the tests.

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SECTION 4.11 RECOMMENDED PRACTICES FOR SHIPPING, HANDLING, APPLICATION AND USE

4.11.1 SHIPPING (1989)

Concrete ties should be shipped in open-top cars. Ties must be securely braced for transportation to prevent any movement that will cause damage. Ties shall be shipped in a horizontal position and braced with spacer blocks in such a manner that the top surface or cast-in-place hardware does not contact ties loaded above. Ties shall not be loaded higher than the top of the cars nor more than six layers deep. The purchaser shall specify the size of shipments in accordance with unloading facilities.

4.11.1.1 Protection of Threaded Inserts

If cast-in place threaded inserts are included in ties, they shall be protected against entry of water and foreign matter by meansof a plastic cap, plug or other suitable device approved by the engineer. Caps or plugs shall be placed in position at the time of manufacture, left in place during shipping and not removed until fastenings are affixed to the ties.

4.11.2 HANDLING (1989)

Unnecessary handling, redistribution and reloading of concrete ties should be avoided. To the extent practical, ties should be distributed in proper position for use without further handling. They shall be unloaded from cars in a manner that will not damage the ties. In no case shall ties be dropped from a truck or car to the roadbed.

4.11.3 PLACEMENT AND INITIAL ROADBED SUPPORT (1988)

In new construction care must be taken to insure that all concrete cross ties are uniformly supported on the roadbed and that nocenter-binding conditions develop prior to ballasting and tamping. If the subgrade condition indicates that there is inadequateor non-uniform support for the ties before placement of ballast, a minimum layer of 3 inches (76.2 mm) of ballast should be placed, leveled and compacted before placement of ties. Ties shall be installed at right angles to the center of track at the designed spacing prior to rail installation.

4.11.4 PLACEMENT OF RAIL AND FASTENINGS IN NEW CONSTRUCTION (2005)

4.11.4.1 Tie Pads

Rail seats should be clean and ties properly positioned prior to placement of pads. Pads should be accurately positioned and centered on the rail seat.

4.11.4.2 Rail

Rail must not be dropped into place. Where continuous welded rail is to be used, the use of rollers is recommended to facilitateits unloading and reduce the risk of dislocating ties and tie pads. Rail shall not be brought into contact with the tie ends duringinstallation. Where rail heaters are used, care should be taken to prevent damage to pads and insulators.

4.11.4.3 Joints

If jointed rail is to be used (see Article 4.1.6.2) special fastenings may required within joint bar limits. Care must be exercised to see that such fastenings are clearly distinguishable and ordered in the proper amount. Care should also be taken to see thatthe actual juncture of two rails does not occur directly over a tie.

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4.11.4.4 Fastenings

Where more than one type of fastening, such as gage and field fastenings or special joint fastenings, are to be used they shallbe clearly marked to avoid confusion and avoid difficulties during their distribution and application. Fastenings shall be applied in the manner appropriate to their design and approved by their manufacturer. If threaded fasteners are used, the shankat the screw shall be dipped in petrolatum before assembly.

4.11.4.5 Corrosion Protection

In corrosive environments, consideration should be given to protecting the external components of fastenings.

4.11.4.6 Insulators

Rail shall be centered before placing insulators. Both insulators at a rail shall be fitted before applying other fastener components. Bars or hammers shall not be used to force insulators into position.

4.11.4.7 Disposing of Concrete Ties

The characteristics of concrete ties allow several options for disposal once their normal service life is over. Options commonlychosen include using concrete ties as riprap for slope stabilization, or sending the ties to a local landfill. Concrete ties aregenerally designated as "Industrial Solid Waste", and such designation must be considered when compliance with Local and Federal Regulation is required. This designation prohibits simple burial within the right of way. Other local requirements, such as insuring that all concrete ties left on the ground as riprap remain above any expected high water line, or complying with environmental regulations concerning Ferro ions, must be met as well.

Crushing of concrete ties has also been successfully done. If this option for disposal is selected, reclamation of scrap metalfrom crushed ties may be economically advantageous.

If concrete ties are only partially damaged, consideration can be given to their reuse in track. In the case of ties on which bothrail seats are intact, but only one rail seat is able to permit satisfactory rail fastening, such ties can be successfully used in yard or other light duty trackage by alternating those rail seats where rail can be fastened. By doing so, both rails are ultimatelysecured at every other rail seat. However, before recycling concrete ties in this manner, verify that this usage is consistent with the expected rail traffic.

4.11.5 TAMPING (1993)

Tamping of concrete ties should be in accordance with the provisions of Chapter 5, Track.

4.11.6 TRACK GEOMETRY (1993)

It is recommended that concrete ties be installed on curves only if the curves have AREMA-recommended, or equal, spiral approach and departure transitions.

4.11.7 SERVICEABILITY (2006)

While cracks and missing concrete are not aesthetically pleasing, most visible imperfections do not compromise the strength of concrete ties. Repairing these imperfections would be for cosmetic purposes only and would not improve the structural integrity of the tie.

Acceptable limits for cosmetic imperfections should be mutually agreed upon by both manufacturer and owner prior to receipt of product.

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4.11.7.1 Center Binding Cracks

Center binding occurs when the tie is supported primarily at the tie center, which can cause cracks to develop in the top centerof the tie. Once support condition is corrected, these cracks close due to the prestressing force on the ties. These ties canremain in track, providing the center binding was not severe enough to cause loss of concrete.

4.11.7.2 Damaged Ends (Missing Concrete)

During the handling, shipping, installation, or maintenance of concrete ties, tie ends can be damaged. This damage can expose tendons, but a significant amount of concrete would need to be removed in order to reduce the strength of the tie. Testing canestablish the parameters of concrete loss that affect structural integrity.

SECTION 4.12 BALLAST

4.12.1 SCOPE (1996)

Refer to Chapter 1, Roadway and Ballast, Part 2, Ballast for all ballast requirements.

SECTION 4.13 TIES FOR TURNOUTS

4.13.1 GENERAL (1993)

a. Concrete ties used in turnouts are subjected to loadings and ballast support conditions considerably different from cross ties in standard track. The trackwork mounted on the ties, and the passage of rail traffic, especially on the turnout track, generate non-uniform dynamic loads which must be considered in the tie design.

b. The dimensions, and tolerances for manufacturing turnout ties are no more critical than standard track ties, but the calculations are much more complex because they must be done precisely for each individual tie in the turnout.

c. The specific provisions below for turnout ties are to be followed in addition to the regular requirements of Part 4, Concrete Ties. Where no specific provisions are stated, the general requirements for concrete cross ties are be used.

4.13.2 LAYOUT (1993)

4.13.2.1 Tie Orientation

a. Ties may be oriented at right angles to the straight track, per Figure 30-4-15, View A in which case the ties with cast in shoulders are different for left hand and right hand turnouts. Ties in sections having the rail fastened to a steel plate, and then the steel plate fastened to the tie, shall be designed for interchangeable use in left and right hand turnouts.

b. Ties may be oriented in a fanned layout per Figure 30-4-15, View B in which case all of the turnout ties may be used for left hand, right hand, or equilateral turnouts. This minimizes the number of different ties which must be produced, and stocked, but the geometric calculations to accurately locate the fastening in the fanned layout are considerably more complex.

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4.13.2.2 Tie Spacing

Tie spacing in the switch section is usually determined by the location of the various switch mechanisms and connecting rods. Care must be exercised to ensure adequate ballast cribs for tamper tool operation. Satisfactory performance has been achieved where a minimum crib width of 7 inches (178 mm) has been maintained, but recesses may be required in the ties as discussed in Article 4.11.3. Beyond the switch section, 24 inches (610 mm) tie spacing can be used. Some variations may be necessary to ensure correct tie placement at the frog, especially in the case of moveable point frogs.

Figure 30-4-15. Tie Orientation

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4.13.2.3 Fastener Placement

a. To follow the curve of the turnout track, it is common for fasteners to require varying degrees of rotation in the ties. For rotation of the shoulders on ties with elastic fasteners, the method shown in Figure 30-4-16 shall be used since it allows the use of standard rail pads, and automatic clip application machines.

b. Track work plates shall be positioned parallel to the centerline of the tie, and the position of all inserts as well as cast inshoulders must be checked to ensure they do not contact the prestress tendons.

4.13.2.4 Ties in Crossovers

Where concrete ties are used in crossovers, either of the methods shown in Figure 30-4-17 may be used at the center portion of the crossover to support the closely spaced tracks.

4.13.3 TIE DIMENSIONS (1993)

a. The turnout tie should have a constant cross section over the entire length. In some cases it may be necessary to make recesses or chamfers to fit heaters, machinery, or other attachments. Recesses are often needed in the sides of ties in the switch section, where temperature changes will cause the point rails, connecting rods, and all attached hardware to shift position.

b. The dimensions in Section 4.3, Tie Dimensions, Configuration and Weight are applicable except as noted in the following sections.

Figure 30-4-16. Preferred Rotation Method for Shoulders in Turnout Ties

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4.13.3.1 Length

The individual tie lengths are calculated based on the turnout geometry. The maximum tie length depends on the track geometry. The minimum tie length must be calculated based on track gage, distance from the rail to the outermost fastening in any tie, and the bond development length of the prestress tendons.

4.13.3.2 Minimum Depth

The minimum design depth of the turnout ties is governed by the design bending moments in Article 4.11.5. Satisfactory performance has been obtained with ties greater than 8.5 inches (216 mm) in depth.

4.13.3.3 Maximum Width

The maximum width of the turnout tie shall not be greater than 12 inches (305 mm). For tie widths greater than 11 inches (280 mm), extra care must be exercised to ensure adequate ballast cribs in the switch and frog sections where tie spacing may be reduced, and switch rods, baskets, etc., are located. These elements will also shift position in the cribs as temperature changes.

4.13.3.4 Rail Cant

The turnout ties normally provide for no rail cant. Where a transition must be made to ties with rail cant, it can be achieved through the use of special trackwork plates, special cast ties, elastic fastening systems, or pre-twisted rails.

4.13.4 DESIGN CONSIDERATIONS (1993)

a. Article 4.1.6.2 recommends that continuous welded rail be used on concrete tie track. For turnouts with concrete ties it is also recommended to fully weld the rails to the points and frog, and to locate any joints which may be required over a ballast crib, rather than over a tie.

b. Field instrumentation may be used to verify loadings in pilot installations, especially in cases where open flangeway frogs are used, or speeds are higher than usual. Instrumentation can also be used to verify support conditions, and the need for maintenance after accumulated tonnage.

c. The minimum pre-compressive stress at any vertical cross section should be 1,000 psi (69 MPa) after all losses and without any applied load.

4.13.5 FLEXURAL STRENGTH (1993)

The minimum unfactored flexural capacity of the turnout ties is shown in the table below, based on the same design considerations as Article 4.4.1 and Article 4.4.2. The ties shall be tested in accordance with the Rail Seat Vertical Load Test described in Article 4.9.1.4, with distance 2 /3 taken as 14 inches (356 mm) for this test.

4.13.6 SUPPORT CONDITIONS (1993)

a. Special care must be given to the support conditions for concrete ties in turnouts to ensure that bending moment capacities are not exceeded. There are many ties where four railseat sections must each have ballast tamped beneath them, and this can cause large negative bending moments when a train passes on any two of the railseats.

Minimum Unfactored Positive Moment Capacity . . . . . . . . . . . . . . . . . . . . . . 390 inch-kips (44 kN-m)Minimum Unfactored Negative Moment Capacity . . . . . . . . . . . . . . . . . . . . . 300 inch-kips (34 kN-m)

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b. Frequently the trackwork in the switch and frog sections covers a substantial portion of the ties, and care must be taken to ensure that ballast is adequately tamped under all ties. Hand tamping may be necessary in some cases to tamp around plated tie sections, heater ducts, or other equipment.

Figure 30-4-17. Ties in Crossovers

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c. Ties oriented in a fanned layout per Figure 30-4-15, View B will require more time for proper surfacing than ties oriented at right angles to the mainline track per Figure 30-4-15, View A.

d. At the option of the Engineer, serrations may be considered in the sides or bottom of the tie to increase lateral resistance in the ballast.

e. Some mechanical equipment may be unable to properly lift and surface the increased weight of concrete ties in turnouts, and assistance with hand jacks may be needed. Also, some mechanical equipment may not be capable of, or may not be set up to tamp ties more than 8 inches (203 mm) deep, and this may cause spalling on the edges of ties. Equipment with sufficient reach must be used to surface concrete turnout ties.

f. The extra length, and stiffness of concrete turnout ties causes a large increase in vertical track modulus. It is recommended that concrete track ties be used at the three entrance points to concrete tie turnouts, so that the change in track modulus is minimized.

4.13.7 TOLERANCES (1993)

4.13.7.1 Camber

Vertical camber in the ties as laid should not exceed 1/1,000 of the ties length. In some manufacturing methods, it may be necessary to check that the horizontal camber does not exceed this value as well.

4.13.7.2 Fastenings

Cast-in inserts and shoulders for fastening systems should be located within ±1/16 inch (1.6 mm) of the position shown on the drawing. Angular tolerance should be within 0.5 degree of the rotation specified.

4.13.7.3 Tie Spacing

Ties should be spaced within ±1/4 inch (6 mm) of the accumulated distance from the point of switch.

SECTION 4.14 TIES FOR GRADE CROSSING PANELS

4.14.1 GENERAL (2005)

a. Concrete ties installed under grade crossing panels may be subjected to conditions different from ties installed in standard track. The ties will be required to carry rail traffic as well as road vehicular traffic.

b. Depending on the type of crossing panel and material, the supporting concrete ties may range in length from 8’3" to 10’0". Tie spacing may vary depending upon application.

c. The use of a crossing tie, which provides a uniformly flat top surface, will provide full and uniform contact with the panel surface. Standard concrete ties provide a contoured top surface which may be suitable for use with crossing panels; however the gauge panel may not make full contact with the tie surface. Elastomer pads are typically placed between the tie and the panel.

d. Concern has been expressed that concrete ties may pump at grade crossing locations since many of these locations are difficult to keep dry. This seems to be a problem related to the heavy-axle freight railroads in the U.S. and less likely in the transit systems and railroads which have lighter axle loads.

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4.14.2 DESIGN (2005)

a. Flexural performance requirements may be determined using the methodology as outlined in Section 4.4 of Chapter 30with consideration given to spacing, tie length, train speed and yearly track tonnage. Similarly, standard design considerations per Article 4.4.2 and test requirements per Article 4.4.3 may be followed.

b. Due to loads being transmitted from rubber-tired vehicular traffic, consideration must be given to the maximum axle-load limits for the particular state highway authority in which jurisdiction the crossing lies and the effect of these loads on the concrete ties.

c. Tolerances and surface finish for the crossing panel ties are to be as outlined in Section 4.3 with the exception of tie length and tie weight. Furthermore, the plane of the top surface of the ties should be controlled as tightly as possible throughout the length of a panel to prevent panel rocking and to ensure uniform panel support.

SECTION 4.15 CAST-IN AND POST-INSTALLED INSERTS FOR CONCRETE TIES

For purposes of this section, an insert is defined as any item embedded into a concrete tie that can later accept an item to beinserted below the level of the concrete exterior surface. Typically these are threaded inserts for accepting bolts or screw spikes. Cast rail fastening shoulders are not covered in this section. Inserts can be either cast-in-place during manufacture of the ties or post-installed in core-drilled holes in ties and secured in place with some type of embedment medium (often grout orepoxy).

Insert types are without limit. However, those typically used in concrete ties are for attaching power rail brackets, running railfastening systems, special trackwork plates, various signal equipment, restraining rails, emergency guard rails, and switch machines.

It is important that inserts used are specified and chosen to provide the necessary performance in track. The performance required will depend on use. However, the following general cautions are independent of use:

a. Inserts must be able to transfer lateral loads into concrete without cracking the concrete surrounding the insert.

b. Inserts must be strong enough to withstand freeze-thaw effects or have some other type of mechanism for protection against such forces. Through holes to allow water to drain, ice pressure absorbing devices, and/or water displacement materials have all been used successfully to prevent freeze-thaw damage.

c. Inserts must be designed to provide necessary torque resistance otherwise they may spin in place or fail in torque.

d. Inserts must be designed to provide necessary uplift resistance for a given thread engagement.

e. Inserts must be designed to provide necessary electrical resistance or impedance if traction power stray current and/or signal shunting is a concern and not provided through other devices.

f. Inserts must be thermally compatible with concrete and the thermal environment encountered in track to prevent damage to the concrete surrounding the insert.

g. Inserts must be adequate to withstand forces resulting from pretensioning or postensioning such that concrete surrounding the insert is not damaged and insert deformation does not impede its function.

h. Inserts must be installed a sufficient distance from the tie end in order to ensure full torque, pullout, and lateral resistance can be achieved.

i. Insert configuration and location shall be chosen to be compatible with the given reinforcing plan so as not to significantly change the structural properties of the tie.

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j. Core drilling holes for post-installed inserts shall not detrimentally affect the structural performance of the tie.

k. Installation of post-installed inserts shall be done in such a manner to provide proper location and be performed in accordance with the embedment medium manufacturer’s recommendations.

l. For post-installed inserts, the embedment medium must provide sufficient adhesion, tensile strength, elongation and also be non-shrink.

SECTION 4.16 CONCRETE TIE REPAIR

Concrete railroad crossties and switch ties at some time in their service life may require some type of repair(s) to permit theircontinued use in track without any significant loss of beam strength or gauge holding capability. These repairs may be required due to derailment, rail seat abrasion, cracks, and/or track maintenance and renewal operations. Repair of cosmetic surface blemishes and defects that do not affect the ultimate strength of the tie, but could affect service life, is also possible.

Common concrete tie repairs are Shoulder Replacement and Railseat Abrasion Repair.

4.16.1 SHOULDER REPLACEMENT OR REPAIR (2006)

Concrete ties with damaged cast in shoulders can be repaired by coring out the damaged shoulder(s) and replacing with new shoulder(s). The economics and amount of time required to use the coring procedure to repair a tie versus replacement of the entire tie should also be considered before proceeding with this process. Experience has shown that a repaired tie is still effective in holding gauge and providing longitudinal restraint.

Replacement of damaged shoulders using the coring process can be done with the rail in place or removed. It may be necessary to use a track jack if the rail is left in place in order to move the rail slightly to avoid nicking the rail base whencoring. Single or double spindle core drills with special carbide and/or diamond tipped concrete core drill bits are normally used to core out the old fastener shoulder and stem(s). Caution is needed during the coring process to ensure that the coring bitdoes not damage pre-stressed tendons. Knowledge of the tendon location within the tie is essential in order to select the correct size of core bit and set the drill up for the proper depth.

Use of a drilling template will ensure correct placement of the drill and bit(s) to properly encircle the shoulder stem(s). Coredstems are then removed (broken off) at the bottom of the stem by tapping the core(s) and shoulder slightly after the bit is removed. The cored plug with shoulder stem can then be removed. Inspect the core to determine if the old stem is intact and whether or not the stem on the new shoulder will need to be ground down in order to fit properly in the hole.

Replacement shoulders should be of the same type, design, and model as the one being replaced in order to fit correctly in the old shoulder cavities with the least amount of adjustment. When replacing shoulders, ensure the new shoulder(s) are positioned for correct height and gauge to ensure proper fit of rail fasteners. Clean the hole(s) with air to remove all dust and water before filling the holes with an epoxy or grout material.

A high strength construction grouting material is needed to secure the new shoulder in the tie. Epoxies or grouts used in thisprocess should meet or exceed criteria listed for Type IV applications identified in ASTM C-881 repair standards. Refer to themanufacturers use instructions to determine the amount of time needed for proper setup and cure of the material used, ambient temperature at time of use, and other conditions that may affect this type repair procedure.

4.16.2 RAILSEAT ABRASION REPAIR (2006)

Various degrees of rail seat abrasion has been found on concrete ties in North America, ranging from minor abrasion of 1-3 millimeters, to heavy extreme abrasion losses of over 10 millimeters in some cases. Methods of repair and materials have been developed to deal with both of these extremes. The primary difference between the procedures is whether or not the loss

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is extreme enough to require a complete rebuild of the tie’s rail seat area, including re-establishing rail seat cant, or to onlyrequire a minor layer of material to protect the area from further erosion and fill small voids and holes.

In track abrasion repair in the 8+ millimeter range requires the use of some type of support form/mold to re-establish the tie’soriginal railseat in conjunction with an appropriate fast setting, self-leveling material. An alternative is to use a non-sag, fast setting material without the use of a form.

Repairs to ties with minor, less severe rail seat abrasion will require considerable less time since most of the rail seat surfaceand cant is still intact. Remove the rail for complete access and inspection of the entire railseat. The railseat area is thencleaned of all old tie pad material and debris. Clean the surface before applying the repair material. Dispense the material directly onto the railseat and spread to cover the entire area. Apply new tie pad system before the material starts to harden,usually within 5-10 minutes after application. Inspect as soon as possible after placing the pad to ensure material has not migrated to the sides of the shoulders, as this could cause problems later when trying to place insulators.

Material for both types of repair should meet or exceed specifications listed in ASTM C-881, Type IV. Use of a temperature controlled, meter-mix dispensing system to apply the repair material for both applications will greatly improve the quality andspeed of application, and keep repair time to a minimum.

COMMENTARY (2015)

The purpose of this part is to furnish the technical explanation of various Articles in Chapter 30. In the numbering of Articles of this Section, the numbers after the “C-” correspond to the Section/Article being explained.

C - SECTION 4.4 FLEXURAL STRENGTH OF PRESTRESSED MONOBLOCK TIES

Monoblock ties are stiff structural members that are loaded by the rails from the top and are supported on the ballast at the bottom. The loads applied at the top combined with the support reactions at the bottom will produce flexure in the ties. Maximum flexure occurs at the rail seats and at the center. Flexure is influenced by a number of factors discussed in Section4.1, General Considerations.

C - WHEEL LOADS

In order to give satisfactory service a prestressed monoblock concrete tie should be capable of withstanding without cracking the maximum loads likely to be found in service.

C - RAIL SEAT LOAD

a. The rail seat load is that load transmitted by rail to the rail seat of the tie. In order to determine the rail seat load, a maximum axle load (AL) of 82 kips (365 kN) was chosen. Therefore, using a distribution factor (DF) of 0.05 for concrete ties spaced at 24 inches (610 mm) centers from Figure 30-4-1 and an impact factor (IF) of 200% from Article 4.1.2.4, the calculated rail seat load (R) is, R = 1/2 (AL)(DF)(1 + IF)

R =

b. This rail seat load is used to determine the flexural requirements in Article 4.4.1, for monoblock ties. The design flexural performance values for monoblock ties for other than 24 inches (610 mm) spacing may be determined directly from Figure 30-4-3 and by applying the appropriate speed and tonnage factors.

12--- 82kips 0.505 1 2.00+ 62.1kips (276 kN)=

Concrete Ties



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C - RAIL SEAT POSITIVE BENDING MOVEMENT

a. The rail seat positive bending moment (MRS+, given as B in Figure 30-4-3) for an 8’-6” tie at 24” center-to-center spacing is calculated using the following assumed support conditions.

Where the bending moment is calculated using, MRS+ = 1.1[(R(L-g)2)/4L], and rounded up to the nearest 5 kip-in. The 10% increase accounts for prestress losses.

Where:R=rail seat load (as calculated above)L=length of tie (in inches)g=rail center spacing (in inches)

MRS+ =

C - CENTER NEGATIVE BENDING MOVEMENT

a. The center negative bending moment (MC-) is calculated using the following assumed support conditions.

Where the bending moment is calculated using, and rounded up to the nearest 1 kip-in.

Where:R=rail seat load (as calculated above)g=rail center spacing (in inches)L=length of tie (in inches)l=center support region=2g-L

=percentage reduction in center support region reaction=1.0 - 0.61 = 0.39

1.1 62.1kips 102 60– 2

4 102------------------------------------------------------------- 300kips - in (34 kNm)=

Concrete Ties



C - BALLAST REACTION

a. The load transmitted to the tie is resisted by the ballast at the interface between the bottom of the tie and the ballast. Immediately following tamping the ballast reaction is concentrated under the tamped portions of the tie with little if any reaction occurring under the center portion of the tie. This condition usually produces positive flexure at the rail seats and the tie center. Over a period of time, because of repeated loads, vibration and crushing of ballast, the ballast will gradually compact, moving away from the areas of greatest concentration. The tie, therefore, settles slightly into the ballast, allowing the center portion of the tie to pick up a portion of the load, thus reducing the amount of load carried by the tie ends.

b. Redistribution of ballast reaction will continue until eventually a condition of uniform ballast reaction over the entire length of the tie is approached. This support condition produces positive flexure at the rail seats and negative flexure at the center of tie.

C - SECTION 4.5 FLEXURAL STRENGTH OF TWO-BLOCK TIES

a. Two-block ties consist of two blocks of concrete connected by a third member. Under load, flexure will occur in the end blocks, and while flexure does occur in the connecting element, its flexural resistance is relatively small; thus one block is able to deflect with respect to the other.

b. Consideration of distribution factor, impact factor, wheel loads, rail seat loads, and tie spacings are the same as for monoblock ties. The rail seat load of 58.5 kips (260 kN) as determined in C - Rail Seat Load is used to determine the flexural requirements in Article 4.5.1 for two-block ties. The design flexural performance values for two-block ties for other than 24 inches (610 mm) spacing may be determined directly from Figure 30-4-5. for reinforced two-block ties and Figure 30-4-6 for prestressed two-block ties and by applying the appropriate speed and tonnage factors.

C - BALLAST REACTION

For two-block ties each tie block must distribute a full rail seat load to the ballast.

C - TIE FLEXIBILITY

a. The connecting element of two-block ties should be sufficiently stiff to maintain track gage and tie integrity during handling, track construction and track maintenance. Under load non-uniform ballast support reactions may cause differential deflection between the blocks of a tie. The connecting element must therefore be flexible enough to accept the maximum deflections likely to occur in track without damage to the element or the concrete blocks.

b. Minimum stiffness and specific deflection without damage requirements have therefore been made a part of these specifications.

C - SECTION 4.6 LONGITUDINAL RAIL RESTRAINT

Rail must be restrained to avoid excessive longitudinal movement. Longitudinal movement of rail can be induced by temperature change and/or traffic. In practice, fasteners on ties with 24 inches (610 mm) spacing providing a longitudinal restraint of 2.4 kips (10.7 kN) per tie per rail for longitudinal movement due to temperature and traffic induced loads have proved satisfactory. In some cases, traffic induced loads may require additional restraint.

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C - SECTION 4.7 LATERAL RAIL RESTRAINT

Truck instability may occur in the wheel-rail interface due to excessive forces interacting between the wheel and rail in the lateral direction. These lateral forces tend to cause wheel flanges to climb the gage side of the rail when there is excessive lateral flange pressure in relation to actual vertical loads. These lateral pressures are caused by one more of the following conditions:

• Nosing or hunting of truck assemblies at a repetitive frequency.

• Centrifugal forces on curved track.

• Impact due to irregular wheel and/or rail alignment or configuration.

• Rotational acceleration of the vehicle body due to curvature changes.

• Wheel friction from curve negotiation.

C - LATERAL FORCES

a. A rational determination of lateral force requirements on track fastenings would be to develop lateral and overturning reactions in the base to the degree that the wheel flanges will climb the rail before the rail would overturn. This limit may be determined by considering the ratio of lateral force to vertical load necessary to cause flange climbing.

b. Studies made show that a ratio of vertical loads (Pv) to lateral forces (PI) approaching unity will permit the wheel flanges to climb the rail. Therefore, using vertical wheel loads of 35 kips (156 kN) generated by a high-horsepower 6-axle locomotive as design criteria for maximum vertical loading (Pv), then we could expect a maximum lateral pressure (PI) to also be in the order of 35 kips (156 kN). Consequently, consideration of the individual lateral forces referred to in C - Section 4.7 Lateral Rail Restraint need not be considered since lateral forces greater than 35 kips (156 kN) would cause wheels to climb.

C - LATERAL FORCE DISTRIBUTION

a. Reference to Figure 30-4-1 covering the distribution of vertical loads to ties indicates that the tie directly under the load will receive from 45% [20 inches (510 mm) centers] to 60% [30 inches (760 mm) centers] of the imposed vertical and lateral loads while adjacent ties will each receive approximately one-half of the balance. This distribution of vertical loading is a function of the rigidity of the track structure, which is greatest about the horizontal axis. The distribution of lateral loads is a function of lateral rail stiffness, tie spacing, frictional characteristics of the fastening system, and lateral fastening system stiffness.

b. However, rail stressed about the vertical axis by pressure induced by a wheel flange has increased stability caused by torsional rigidity of the rail and the effect of the weight from wheels of adjoining trucks. The calculations to compare the two conditions of loading are complex, but for our purposes the resistance to bending in the vertical and horizontal axis are in the same order of magnitude under these conditions. Therefore, lateral loads applied to the tie may be expected to be distributed in a manner similar to vertical loads. However, this theoretical assumption may be too generalized since filed observations suggest that lateral loads are distributed to less ties than vertical loads. Consideration of lateral load distributions should be taken independently of vertical load distribution in the design of ties and fasteners. Based on the foregoing, the tie fastening system accommodates the following design stresses in combination:

c. Horizontal Reaction:

Lateral force Distribution Factor (DF)

Concrete Ties



d. Vertical Reaction:

C - SECTION 4.8 ELECTRICAL PROPERTIES

C - SIGNAL CIRCUITS

The engineer must give consideration to the electrical environment in selecting concrete tie designs and specifications. While concrete is not a good conductor of electricity, it does not have sufficient resistance or impedance, particularly when steel reinforcement is in close proximity to rail fastening components, to insure trouble-free operations of signal appliances depending upon electrical isolation of the rail if the rails are not insulated from the concrete. From the view point of signaloperation, the value of concern is the impedance per 1,000 feet (305 m) of track rather than impedance per tie. The former includes electrical leakage through ballast as well as the ties which can be expected to perform in wet trackage, and under a variety of voltages, both ac and dc.

C - ELECTRIC TRACTION

Electric traction systems most often rely upon ground return through trackage for circuit completion. Under these circumstances, it is desirable that the impedance between rails and ground (ballast and subsoil) not exceed certain maximum values.

LateralaForce Rail HeightRail Base

-------------------------------- Vertical Load2

--------------------------------------– DF

30-5-1

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30, ParPart 5

Engineered Composite Ties

— 2012 —

FOREWORD

This specification is intended to provide necessary guidance in the design, manufacture, and use of engineered composite ties and their components for main line standard gage railway ballasted track systems. Engineered composite ties include both polymer composites and engineered wood products. The specification contains minimum performance requirements for components of engineered composite tie railway track. Track constructed of tie and fastener components meeting the specifications applicable to the anticipated usage should be expected to give satisfactory performance under current AAR-approved maximum axle loads.

The specification covers materials, physical dimensions, physical properties, and structural strength of engineered composite ties. The specification does not cover techniques or equipment for the manufacture of engineered composite ties or special fastenings.

Engineered composite ties are a relatively new technology compared to the more conventional sawn wood, concrete, or steel ties. Passages of this specification, especially those pertaining to polymer composites ties, include commentary considered beneficial to help the engineer responsible for track design to better understand the sometimes unique properties of these materials. This specification will be revised as appropriate using data generated by ongoing laboratory and field testing and in-service experience.

Where current specifications or recommended practices of other technical societies, such as ASTM International are appropriate, they are made part of this specification by reference.

TABLE OF CONTENTS


5.1 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-25.1.1 Introduction (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-2

5.2 Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-35.2.1 General (2003) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-35.2.2 Composite Tie Types (2003) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-4

5.3 Physical and Mechanical Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-45.3.1 General (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-45.3.2 Dimensional Requirements (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-55.3.3 Performance Requirements (2009) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-5


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5.4 Special Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-75.4.1 General (2003) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-75.4.2 For Engineered Polymer Composite (EPC) Ties (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-85.4.3 For Engineered Wood Product (EWP) Ties (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-9

5.5 Quality Control, Inspection, and Identification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-115.5.1 Production Quality Control (2010). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-115.5.2 Tie Identification and Records (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-125.5.3 Certification (2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-12

5.6 Engineered Composite Ties for Open Deck Bridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-125.6.1 Applicability (2012) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-125.6.2 General (2012) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-125.6.3 Material (2012). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-135.6.4 General Requirements (2012). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-135.6.5 Structural Requirements (2012) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-155.6.6 Design Validation Tests (2012) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-155.6.7 Production Quality Control of Alternate Material Open Deck Bridge Ties (2012) . . . . . . . . . . . . . . 30-5-18

LIST OF FIGURES


30-5-1 Engineered Wood Product Orientations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-1030-5-2 Tie Bending Test Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-17

LIST OF TABLES


30-5-1 Physical and Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-730-5-2 Tie Bending Deflection Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-5-17



a. In supporting and guiding railway vehicles, the track structure must restrain repeated lateral, vertical, and longitudinal forces in order to maintain surface, line, and gage. As elements of the track structure, individual ties receive loads from the rails or fastenings, and in turn they transmit loads to the ballast and subgrade. Consequently, the design of a tie affects and is affected by characteristics of other components of the track structure. Engineered composite ties combine two or more materials (e.g., selected reinforcing elements and/or fillers) in a matrix binder to obtain properties superior to the individual components. The two general types of engineered composite ties covered by Part 5 are:

© 2013, American Railway Engineering and Maintenance-of-Way Association© 2014, American Railway Engineering and Maintenance-of-Way Association© 2015, American Railway Engineering and Maintenance-of-Way Association




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(1) Engineered polymer composite (EPC) – a material system that incorporates reinforcements (e.g., glass fibers) and/or other property modifiers in a polymer matrix.

(2) Engineered wood product (EWP) – wood laminates or strands bonded together with a structural adhesive (e.g., phenolic).

b. While the use of engineered composite ties may require some different considerations in design and installation, the products can be used both in new construction and as maintenance ties for a standard wood tie track structure.

c. Engineered composite ties are designed to utilize the same tie spacing and ballast structure as wood ties. The ties can be installed using conventional cut spikes or screw spikes with standard installation equipment. Specific installation details, such as which spikes work best, size of predrilled holes, etc., should be based on the tie manufacturer’s recommendations.

d. For increased lateral and longitudinal track stability, polymer composite ties can be manufactured with specially designed surface patterns to create a mechanical interlock between the tie and the ballast. Individual manufacturers have different proprietary designs to provide a range of lateral track stability. Use of surface-modified ties is particularly recommended with welded-rail track, which can apply significant lateral and longitudinal loads to the track structure due to thermally induced strains in the rail.

e. The analysis of requirements for such systems must necessarily involve not only the tie but also all components of the track system, their interdependency, and the conditions under which they must be applied. Thus, engineered composite tie track systems involve:

(1) A well designed track structure that includes the rail, tie fastenings, ties, ballast, and subgrade.

(2) The quality of each component, installation, and maintenance.

(3) The magnitude, and frequency of traffic-imposed loads, the effect of environmental factors such as temperature and weather, and the overall economics of installation and maintenance.

(4) The need to support and guide railway vehicles while restraining repeated lateral, vertical and longitudinal forces.

f. The performance specifications that follow provide the basic guidance needed in the selection, design, and application of engineered composite tie systems. Success in their application will require careful supervision on the part of the engineer to ensure that all components meet required standards and that the system is properly installed and maintained.

SECTION 5.2 MATERIAL

5.2.1 GENERAL (2003)

A composite is a material formed from two or more distinct materials (e.g., a polymer binder with reinforcement in the case of polymer composites, and wood laminates bound with structural adhesive in the case of engineered wood products) to obtain specific properties that are superior to the individual components.


Ties



5.2.2 COMPOSITE TIE TYPES (2003)

5.2.2.1 Engineered Polymer Composite (EPC) Ties

a. Polymer composite ties incorporate a polymer matrix, typically post-consumer recycled high-density polyethylene (HDPE) as a primary component, with reinforcing fibers and/or fillers to contribute enhanced properties. In general, polymer composite ties may be classified as one of three generic composite types:

(1) Fiber-reinforced polymer composite – polymer reinforced with fibrous glass or other fibers, including polymeric fibers. Fillers and other modifiers may also be added to enhance particular physical or mechanical properties.

(2) Particle-reinforced polymer composite – polymer modified with dispersed small particles to enhance particular physical and/or mechanical properties.

(3) Hybrid composite – a composite that incorporates two different reinforcement fibers or other structural components (e.g., a concrete, steel, and polymer combination).

b. Each of the above-described engineered polymer composite ties has different ranges of properties, costs, and operating characteristics. However, each type of polymer composite tie can be manufactured to meet the established recommended performance specifications (Section 5.3 below) for use in track under AAR-approved maximum axle loads.

5.2.2.2 Engineered Wood Product (EWP) Ties

a. EWP consists primarily of wood laminates or strands bonded together with a structural adhesive (e.g., phenolic). Orientation and/or placement of the wood laminates/strands is critical to the resultant structural and physical properties.

b. The following tie types are currently considered under this specification:

(1) Glued-Laminated (Glulam) Tie – an engineered wood composite manufactured by bonding together softwood or hardwood dimensional lumber using exterior-grade structural adhesives (e.g., phenolics).

(2) Parallel Strand Lumber (PSL) Tie – a structural composite lumber product manufactured using softwood strands (typically 0.1 inch by 1 inch by 96 inch [2.54 mm by 2.5 cm by 2.44 m]) laminated together using structural exterior adhesives (e.g., phenolics).

SECTION 5.3 PHYSICAL AND MECHANICAL PROPERTIES

5.3.1 GENERAL (2006)

Engineered composite ties shall meet the following general requirements:

a. Tie shall permit the application of standard rail, tie plate, and hold-down fasteners, such as screw spikes or cut spikes, without requiring special procedures for installation other than ordinary predrilling of the tie per the manufacturer’s requirements.

b. Tie shall provide an adequate flexural response to absorb train induced vibrations, while possessing sufficient vertical compressibility to withstand rail seat loading. Tie must support imposed railroad-type loadings while maintaining surface, line, and gage. Tie must transmit traffic loads to the ballast with diminished contact pressures and anchor the rail-tie structure against lateral and longitudinal movements.





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c. Material surfaces shall have slip resistance equal to or better than a standard treated wood tie.

d. Tie shall not be prone to failure (e.g., cracking or fracture) due to weather-related changes in temperature.

e. Tie shall not warp or sag to the level of permanent deformation that would require replacement of the tie.

f. Tie shall not split or crack in anyway requiring the tie to be replaced.

g. Material surface degradation due to solar ultraviolet (UV) radiation exposure shall not exceed 0.003 inch (0.076 mm) per year.

5.3.2 DIMENSIONAL REQUIREMENTS (2006)

a. All measurements performed for quality assurance purposes shall be made at 73.4 +/- 2 F (23 +/- 1.1 C) and relative humidity of 50 +/- 5%. Alternatively, measurements may be made at ambient temperature and humidity conditions and then corrected to the specified temperature and humidity. In case of dispute, the standard conditions shall govern.

b. For a standard gage track tie, the rail-bearing areas are those sections between 20 inches (510 mm) and 40 inches (1020 mm) from the center of the tie. Tie surface flatness in the area of the tie plate shall be within 0.125 inch (3.18 mm).

c. Tie dimensions as specified shall be full size. All ties, without surface texturing, shall have a thickness tolerance + 1/4 inch (6.4 mm), -0 inch (0 mm); width tolerance +/- 1/4 inch (6.4 mm); length tolerance +3/4 inch (19 mm), -0 inch (0 mm). Ties with surface texturing shall meet nominal specified dimensions as required for the application.

d. Standard ties, 7 inch (178 mm) by 9 inch (229 mm) by 8.5 to 9 foot (2.6 m to 2.7 m) long, without surface texturing, will be considered straight when a straight line along each tie face from the middle of one end to the middle of the other end is no closer to the edge of the tie than one-half the tie face dimension, plus 1/4 inch (6.4 mm) or minus 1/4 inch (6.4 mm). For ties surface textured for increased track stability, this tolerance shall be a maximum plus 3/4 inch (19 mm) or minus 3/4 inch (19 mm).

5.3.3 PERFORMANCE REQUIREMENTS (2009)

5.3.3.1 Laboratory Testing

a. Engineered composite ties shall meet the physical and mechanical performance requirements listed in Table 30-5-1.

b. Additional tie performance tests are described in Part 2 of Chapter 30, Evaluative Tests for Tie Systems. Perform these additional tests as required noting that performance criteria have not been fully developed for engineered composite ties for each of these tests.

c. Additional properties, and a comparison of values to various other tie materials and products, are listed in Table 30-A-1., Mechanical Properties; Table 30-A-3., Rail Fastening System; and Table 30-A-4., Environmental Properties,located in Chapter 30, Appendix - Crosstie Performance Matrix.

5.3.3.2 Recommended Additional Testing

5.3.3.2.1 Field Service Testing

The performance properties listed in Table 30-5-1 are for laboratory-scale evaluations and do not represent actual operating exposures. Engineered composite ties can be fabricated under this specfication using many different material compositions, designs, and processing, any of which can have an affect on tie performance in track. Compliance with the listed laboratory requirements does not necessarily assure satisfactory performance of the ties in actual service conditions. Demonstration of field performance in actual track is, therefore, highly recommended before any large-scale purchase and installation of any given manufacturer’s composite ties. A field test zone of a minimum 100 ties is recommended. The ties shall be installed in amanner that replicates standard installation practice and hardware for the particular road while conforming to any special


Ties



product specific requirements by the manufacturer (e.g., size of pre-drill). 100 million gross tons (MGT) of traffic loading isrecommended as a minimum evaluation cycle while monitoring the track conditions including, but not limited to, unacceptable gage spreading, fastener uplift, and tie cracking or splitting.

5.3.3.2.2 Accelerated Weathering Testing

Ties can lose their serviceability not only because of wear due to mechanical loading but because of exposure to the weather.In the early-1990’s, an empirically-based test method was developed to assess the accelerated weathering properties of wood or wood-based ties. This method is considered to be equivalent to about 20 to 25 years of outdoor track service in the Midwestand can be found on page 82, Report No. R-702; and on page 18, Report No. R-915, Association of American Railroads Research and Test Department (AAR). While the exposures used in this method may or may not be the most appropriate for determining the accelerated weathering properties of EPC ties, the method is considered a reasonable basis of comparison in the absence of a method specifically developed for EPC ties. The test method consists of 6-cycles of exposures to vacuum-pressure soaking, freezing, steaming, and dry-oven conditioning. The results are expressed as a percent loss of tie mechanicalproperties after the exposure cycles.





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Table 30-5-1. Physical and Mechanical Properties

* Values for EWP ties include effects from pressure treatment and moisture content between 19% and 28%

TBD = to be determined

N/A = not applicable

SECTION 5.4 SPECIAL CONSIDERATIONS

5.4.1 GENERAL (2003)

In general, both polymer- and wood-based composite ties are applicable as substitutes for solid sawn wood ties in track. Whiletheir use, handling, and installation are similar to sawn wood, some unique material properties of these composites require

Tie Type

PerformanceCharacteristic

Test Method Polymer Composites

GluedLaminated*

StructuralComposite Lumber*

Modulus of Elasticity (in bending - center negative) – MOE, psi (MPa)

Part 2,Section 2.2.3,

Test 1C

Minimum, 170,000(1,170)

Average, 1,700,000(11,700)

calculated per ASTM D3737

Average,1,740,000(12,000)


Modulus of Rupture (in bending - center negative) – MOR, psi (MPa)


Test 1C

Minimum,2,000(13.8)

Minimum,9,700(66.9)


Minimum,7,800(53.8)


Rail Seat Compression, psi (MPa)

Part 2, Section 2.3,Test 2

Minimum,900(6.2)

Minimum,650(4.5)

MinimumTBD

Single Tie Lateral Push, lbf (kN), after 100,000 gross tons of traffic


Minimum,2,500(11.1)

Minimum,1,800(8.0)

Minimum,1,800(8.0)

Spike / Screw Pullout, lbf (kN)


Test 3A

Minimum,1,900 / 5,000(8.5 / 22.2)

Minimum,TBD

Minimum,TBD

Coefficient of Thermal Expansion, in/in/oF (cm/cm/ oC)

ASTM D6431 Maximum,7.5 X 10-5

(1.35 X 10-4)

N/A N/A

Electrical Impedance, ohms


Minimum,20,000

Minimum,10,000

Minimum,10,000


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special considerations for their selection and use. These special considerations are presented in this section. Consult the manufacturer for any additional specifics.

5.4.2 FOR ENGINEERED POLYMER COMPOSITE (EPC) TIES (2006)

5.4.2.1 General

There are several manufacturers of EPC ties and their products exhibit a range of properties. The ties can be produced in standard cross sections and lengths. The manufacturing process for EPC ties results in ties of uniform cross-section (e.g., 7 inch [180 mm] by 9 inch [230 mm] rectangle) but virtually any desired shape can be achieved, if required. Weight per tie is between 185 and 320 pounds (84 and 145 kg), depending on size and composition. Certain unique characteristics of EPC ties require special considerations that may impact the selection and design of EPC systems. These considerations are detailed below.

5.4.2.2 Thermal Properties

a. A characteristic property of EPC ties is a higher thermal expansion coefficient than wood, concrete, steel or EWP. Theoretically, this means that EPC ties could grow longer or shorter with changes in temperature as compared to the other tie materials for the same changes in temperature. However, field experience in a variety of locations and climates has shown that gage is not affected to the degree predicted by direct calculations. The specification requirement for thermal expansion ensures that rail gage will be maintained over a wide range of operating temperatures.

b. While EPC ties will undergo, at least, some dimensional changes due to changes in temperature, it should be noted that these changes do not occur instantaneously with the change in ambient air temperatures. The polymer matrix materials used in these ties are inherently poor heat conductors. While the surface of the tie may exhibit a rapid change in temperature (e.g., when exposed to direct sunlight), the bulk of the tie will not. Changes in gage will normally not be seen as a result of changes in temperature over a single day-to-night cycle. However, over more long-term seasonal changes in temperature, gage dimensions will be affected – increasing as the temperature gets higher and decreasing as the temperature gets lower – as the bulk of the tie material has time to reach a thermal equilibrium at the new seasonal temperature.

c. If EPC ties are installed at ambient temperatures below 40 F (4 C) or above 100 F (38 C), the gage should be adjusted by 0.125 inch (3.2 mm) (tighter at cold temperature installations, greater at high temperatures) or as otherwise recommended by the manufacturer.

5.4.2.3 Electrical Properties

The polymer matrices used in the manufacture of EPC ties are, by their nature, excellent electrical insulators (i.e., poor conductors). However, if metallic components are incorporated into the tie design, care must be taken to avoid these metallic inserts during rail fastening in order to avoid rail-to-rail shorts.

5.4.2.4 Spike Withdrawal

a. Laboratory tests have shown that the force required to withdraw screw spikes from EPC ties meets or exceeds the force required for wood ties. However, laboratory test results for the withdrawal of cut spikes show the forces to be initially lower for EPC ties than for wood ties (e.g., the average of several manufacturers’ results for cut spike withdrawal exceeded 2,000 pounds-force [8.90 kN] versus 8,500 pounds-force [37.8 kN] for red oak). Other laboratory and actual service results indicate that cut spike hold in EPC ties may not significantly deteriorate over time. In fact, over a six-cycle accelerated aging test at the University of Illinois, the spike withdrawal strength of EPC ties actually improved 10 percent while the oak ties decreased more than 77 percent, to 1,900 pounds-force (8.45 kN). These data illustrate that EPC ties may have a higher hold strength than oak ties over time.





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b. Actual operating data support the observation stated above and the ability of the EPC ties to hold both cut spikes and screws. In three different installations at the Transportation Technology Center, Inc. Facility for Accelerated Service Testing, in Pueblo, CO, and on commercial freight track, EPC ties have carried in excess of 535 million gross tons (MGT) (4.85 x 105 gross kg) of traffic without spike or fastener failures, and the ties continue to accumulate load.

5.4.2.5 Lateral Track Stability

EPC ties can be surface-textured for enhanced lateral stability over untextured EPC ties. As newly installed wood ties accumulate traffic, the ballast will dig into the surface of the wood to effectively increase the overall track stability. With an appropriately modified surface, EPC ties can immediately provide enhanced track stability over untextured EPC ties and wood ties without the need of accumulated rail traffic. Ties can be textured on the bottom and/or on the two sides as required for theanticipated track application. Based on single-tie lateral push-out tests performed by various laboratories including TTCI, EPC ties without the surface texturing have not exhibited increased lateral track stability from that achieved during initial tieinstallation even after high traffic loading. EPC ties without surface texturing maintained a 2,000 lbf (8.9 kN) or less push-outforce even after 15 MGT (1.36 x 104 gross kg) of traffic. With surface texturing, this push-out force increased to 4,000 lbf (17.8 kN) or more without any accumulated traffic tonnage. Use of surface-modified ties is particularly recommended with welded-rail track, which can apply significant lateral and longitudinal loads to the track structure due to thermally induced strains in the rail.

5.4.2.6 Preservative Treatment

EPC ties are inherently resistant to rot and insects and, therefore, do not require additional treatment processes.

5.4.2.7 Machining

Typically, EPC ties can be bored, branded, incised, or trimmed with the same machinery and processes as used for sawn lumber ties. The manufacturer’s recommendations should be followed.

5.4.2.8 Tie Plugs

Tie plugging material may be used in EPC ties basically in the same fashion as they are used in sawn ties. Polymer-based plugging compounds (e.g., polyurethane) are recommended.


Anti-split devices are not required for EPC ties.

5.4.2.10 Disposal

The thermoplastic matrix of most manufactured EPC ties increases the probability that worn out or damaged EPC ties can be recycled into the manufacturing process to make new EPC ties. Consult the manufacturer regarding specific recycling options. Federal, State, and local regulations may also influence the ultimate disposal method.

5.4.3 FOR ENGINEERED WOOD PRODUCT (EWP) TIES (2006)

5.4.3.1 General

By virtue of their wood-based composition, EWP ties behave similar to solid sawn wood ties in many respects. However, because they are engineered composites, they also have some unique properties that can impact the selection and design of EWP systems. These considerations are detailed below.


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5.4.3.2 Adhesives

Adhesives shall be suitable for use with wood in exterior structural applications. Adhesives shall meet the requirements of ASTM D 2559.

5.4.3.3 Species

EWP ties may be of any wood species provided that the manufacturer certifies the minimum mechanical properties of EWP product.

5.4.3.4 Preservative Treatment

EWP ties may have physical properties that differ from sawn lumber ties. These differences (e.g., permeability) may influence the material’s treatability, and, therefore, specialized treatment processes may be required. EWP ties shall be treated in accordance with the manufacturer’s recommendations.

5.4.3.5 Strand/Laminate Orientation

EWP ties have a distinct strand/laminate orientation not seen in sawn timbers (Figure 30-5-1). The orientation influences mechanical and structural properties, and it results in different surface characteristics and appearance. It is important to followmanufacturer’s recommendations with regard to orientation, particularly with square members such as bridge ties.

5.4.3.6 Machining

Typically, EWP ties can be adzed, bored, branded, incised, or trimmed with the same machinery and processes as sawn lumber ties. The manufacturer’s recommendations should be followed.

5.4.3.7 Tie Plugs

Tie plugging material may be used in EWP ties in the same fashion as in sawn ties. The specifications for wooden tie plugs arelocated in Article 3.1.5.


The need for anti-split devices on EWP ties may vary. Consult the manufacturer for recommendations. If required, use of anti-splitting devices shall be in accordance with Article 3.1.6 and Article 3.1.7.

Figure 30-5-1. Engineered Wood Product Orientations

© 2014, American Railway Engineering and Maintenance-of-Way Association© 2015, American Railway Engineering and Maintenance-of-Way Association




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5.4.3.9 Inspection

EWP ties may contain fewer knots, shakes, splits, checks, slope of grain, or bark seams than sawn ties. Inspection of EWP tiesshould be in accordance with Article 3.1.1.4.

5.4.3.10 Disposal

Treated EWP ties can be disposed of in the same manner as conventional wood ties. Federal, State, and local regulations may dictate acceptable disposal methods.

SECTION 5.5 QUALITY CONTROL, INSPECTION, AND IDENTIFICATION

5.5.1 PRODUCTION QUALITY CONTROL (2010)

5.5.1.1 General

a. By virtue of the broad definition of engineered composite ties, each manufacturer will likely have proprietary formulae using different combinations of materials for the matrix, reinforcements, fillers, and additives to meet the performance requirements established for these products. Likewise, the manufacturing processes may also vary for the different products, using a range of temperatures, pressures and processing steps to produce the finished ties.

b. In order to provide a consistent quality assurance format to evaluate the various engineered composite ties without requiring railroad customers to become composite material processing experts, it is recommended that each manufacturer adhere to an independent quality assurance protocol and evaluation. Among the acceptable standards ratings would be AAR M-1003 or ISO 9001-2000. It is recommended that composite tie manufacturers provide assurance that their product is manufactured in a process that meets one of these standards or a defined and acceptable alternative as agreed upon by both buyer and seller.

5.5.1.2 Minimum Requirements

At a minimum, the quality assurance program shall include the following:

a. Material Specification, including incoming material inspection and acceptance requirements.

b. Sampling and inspection frequencies shall be devised to encompass all variables that affect the quality of the finished product including lot-to-lot variations from different production runs. Increased frequencies shall be used in connection with new or revised facilities. A random sampling scheme shall generally be used for specimen selection. As a minimum, properties to be verified in the Quality Assurance program shall include:

(1) Dimensional Requirements, Article 5.3.2

(2) Modulus of Elasticity and Modulus of Rupture, Article 5.3.3, Table 30-5-1

NOTE: Depending on composition and fabrication process, EPC ties will contain internal voids not visible to the naked eye, particularly in the center of the cross-section. An evenly distributed fine foam in the center cross-section is considered normal. However, large internal voids can occasionally form that can negatively affect tie performance. Since such internal voids may not be obvious upon inspection of the outside of the tie - including the ends, manufacturers of EPC ties are encouraged to develop procedures to screen finished ties for these unacceptable internal voids.

c. Procedures to be followed upon failure to meet specifications or upon out of control conditions shall be specified. Included shall be reexamination crieteria for suspect material and material rejection criteria.


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d. Finished product marking, handling, protection, and shipping requirements as they relate to the performance of the finished producct shall be defined.

5.5.1.3 Inspection Personnel

All manufacturing personnel responsible for quality control shall have knowledge of the inspection and test procedures used to control the process of the operation and calibration of the recording and test equipment used and of maintenance and interpretation of quality control records.

5.5.1.4 Record Keeping

All pertinent records shall be maintained on a current basis and be available for review. Records shall include:

a. Inspection reports and records of test equipment calibration, including indentification of personnel conducting tests.

b. All test data, including re-testing and data associated with rejection production and corrective actions taken.

5.5.1.5 Retest and Rejection

If the results of any selected quality tests do not meet the requirements, the test(s) may be conducted again in accordance withstatistically valid sampling techniques as agreed upon between the purchaser and the seller. There shall be no agreement to lower the minimum requirements or omitting tests that form a part of this specification, substituting or modifying a test method or by changing the specification limits. In retesting, the product requirements of this specification shall be met. Ifupon retest failure occurs, the quantity of product represented by the tests(s) shall be rejected.

5.5.2 TIE IDENTIFICATION AND RECORDS (2006)

Finished ties will permanently identify the manufacturer and year and month of production. In addition, product shipments will be traceable to the year, day, production line, and operating shift that produced the ties.

5.5.3 CERTIFICATION (2006)

When requested, a manufacturer’s cerfication and any other documents required to substantiate certification shall be furnished stating that the ties were manufactured to meet this specification.

SECTION 5.6 ENGINEERED COMPOSITE TIES FOR OPEN DECK BRIDGES

5.6.1 APPLICABILITY (2012)

The purpose of this part is to provide recommendations for open deck bridge ties made of materials other than timber (alternative or composite materials). Design of ties made from wood product derivatives such as glued-laminated timber and parallel-strand lumber should meet the requirements in Chapter 7; design of steel ties should meet the requirements in Chapter 15. Bridge decks with direct fixation of the rail or concrete ties are not covered by this Part and require special evaluation.

5.6.2 GENERAL (2012)

Bridge ties must meet general track tie requirements including ability to hold track gage, surface, and alignment. This includes, but is not limited to, parameters such as: wear/abrasion resistance, tie plate cutting resistance, fastener retention,dimensional stability, electrical impedance, durability, and fire resistance. Reference Chapter 30, Article 5.3.3.1.b.





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a. Bridge ties for open deck bridges are normally attached to the bridge superstructure with hook bolts or similar fastening systems, and often also dapped. Therefore there is no need nor applicability for the single tie lateral push test requirement as found in Part 2. Alternative or composite ties for open deck bridges shall meet all the requirements of Chapter 30 which apply to general track ties, with the exception of single tie lateral push testing (Section 2.9, Test 8).In particular, requirements for physical and mechanical properties detailed in Chapter 30, Part 5, Article 5.3.1 apply.

b. For structural bridge ties loaded in bending, the ties also act as a structural bending member and shall be tested according to Articles 5.6.6.2 and 5.6.6.3 below. In addition, they must undergo quality control testing during production as recommended in Article 5.6.7.

c. For bridge ties not loaded in bending (bearing ties), the requirements of Articles 5.6.6.2 and 5.6.6.3 and Article 5.6.7need not be met.

d. Ties used to carry walkways or other appurtenances are to be evaluated as structural ties unless fully supported in bearing.

5.6.3 MATERIAL (2012)

Bridge tie materials shall meet the following in addition to the requirements in Part 5, Section 5.3.

a. Deterioration / weathering performance at a minimum should be comparable to that of a treated timber tie:

(1) A design service life of 40 years or longer should be considered for bridge ties.

(2) Bridge ties shall be resistant to fuel spills and resistant to any specific service conditions or chemical environments expected to be encountered, as recommended by the Engineer.

(3) Bridge ties shall be resistant to other environmental conditions as per Chapter 30, Table 30-A-4.

b. Material for open deck bridge ties should be at least as fire resistant in railway service as timber bridge ties with respectto:

(1) Flammability

(2) Toxicity or environmental hazard

(3) Heat generated during combustion

(4) Duration of fire.

NOTE: A laboratory test for fire resistance is under development.

c. Alternate material open deck bridge ties shall have a maximum coefficient of thermal expansion as recommended in Table 30-5-1.

5.6.4 GENERAL REQUIREMENTS (2012)

Depending on the intended service conditions, bridge ties may be classified as structural or bearing ties. Structural ties arenormally used on open deck bridges having steel spans. Under these conditions, the design of the ties is governed by flexure strength or shear strength. Bearing ties are normally used for open decks of timber trestle spans or on open decks of steel beamspans having four or more beams where the design of ties is governed by bearing strength on the top of the stringer flange.

The recommendations for structural performance are given beginning in Article 5.6.5.


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Performance requirements for bearing ties are similar to those for track ties. Bearing ties for bridges shall meet the requirements of Part 2 for rail seat bending and tie center bending.

a. Bridge ties shall not interfere with signal circuits (Chapter 30, Section 2.8, Test 7 – Fastener Electrical Impedance Test).

b. Bridge ties shall be suitable for severe outdoor service under a wide range of weather conditions:

(1) Bridge ties shall maintain structural integrity and dimensional stability for the temperature range of -50 F (-46 C) to 140 F (60 C) or as otherwise specified by the Engineer.

(2) Bridge ties shall maintain structural integrity and dimensional stability for a humidity range of 5 to 100 percent.

(3) This section may imply that structural load testing as per Article 5.6.6 is required at a wide range of temperature and humidity conditions depending on the tie’s sensitivity to temperature and humidity. It is intended to prevent ties from deteriorating due to changes in temperature and/or humidity. It is also intended to ensure that ties maintain proper track gage, surface and alignment for the intended range of service temperatures and humidity. The need for structural load testing at various temperature and humidity conditions will be determined by the Engineer.

c. Bridge ties shall have the ability to be handled with standard bridge/track machinery. Factors to consider include, but are not limited to:

(1) Weight

(2) Hardness

(3) Brittleness

(4) Resistance to chipping.

d. Bridge ties should demonstrate performance similar to timber ties under extreme impact load, i.e. derailment.

e. Bridge ties should be able to mold around web projections and rivets or bolt heads with no adverse effects. Alternatively, there may be other means to allow for these projections without damage to the tie.

f. Bridge ties should be suitable for drilling and framing to accommodate various installations.

g. Bridge ties should have the ability to be used with standard track and bridge hardware (deck fasteners, tie plates, rail anchors, tie spacers, etc). Alternatively, the supplier should provide special handling and framing details that have been approved by the Engineer.

h. Allowable bearing capacity on the side of a tie must be at least equal to that of a timber bridge tie in order to provide adequate rail anchor resistance.

i. Bridge ties should have a life cycle equivalent to or greater than that of a treated timber bridge tie (estimated 40 years) under dapped or un-dapped conditions (both fatigue life and deterioration requirements).

j. Bridge ties should result in a deck not more than 10% heavier than one made of timber at conventional spacing, unless otherwise approved by the Engineer. Particular attention shall be given to cases where the bridge capacity might be reduced due to increased dead load. For movable bridge spans, weight balance is critical and weight must be approved by the Engineer.

k. Bridge ties should not be subject to excessive creep or long term deflection. This is particularly a concern for ties supporting walkways, as well as for other structural (bending) ties. Creep at any point on a tie shall be limited to L/250,





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where L is equal to the girder spacing (center-to-center) for structural ties, and L is equal to the rail spacing (center-to-center) for bearing ties.

l. Bridge ties should provide a suitable walking surface.

5.6.5 STRUCTURAL REQUIREMENTS (2012)

5.6.5.1 Scope / Applicability

Recommendations of this part assume that alternative ties for open deck bridges will utilize similar tie dimensions and tie spacing as conventional timber bridge deck ties. Typical sizes and maximum clear spacing for bridge deck ties are tie widths of8 to 12 inches, clear tie spacing of up to 6 inches, and tie depth determined to meet strength requirements. Tie length will bedependent upon girder spacing, spacing bars, and walkway requirements. Tie depth for 8-foot girder spacing is often around 12 inches, but is dependent upon timber species and bridge design.

Wider girder spacing will typically require greater tie depth in order to meet the structural performance guidelines. For standard gage track, wider girder spacing leads to a greater bending moment which the tie must resist.

The recommendations for structural performance are based on the ability of a tie to meet test requirements. Deflections rather than stresses are specified as stresses are material specific.

a. Recommendations of this part assume standard tie plate widths.

b. Recommendations of this part may yield different tie designs or depths for different girder spacings, track gages, or other changes in loading and support conditions.

5.6.5.2 General

a. Structural (bending) ties for open deck bridges shall have adequate strength in bending, shear, and bearing. In addition, structural (bending) ties shall have adequate stiffness and deflection performance.

b. The tests in Article 5.6.6 are designed to evaluate performance of a particular bridge tie design and intended girder spacing. Therefore successful evaluation of a particular dimensional design does not necessarily apply to ties with different dimensions or intended for different girder spacing.

5.6.5.3 Design Load

Design load case shall be the Cooper E-80 Live Load specified in Chapter 15, Article 1.3.3 and distributed per Article 1.3.4.1.Impact load shall be 100 percent. Factor of safety shall be 2.0. (This results in a design live load of 53,300 lbs per rail seat.)

5.6.5.4 Other Structural Performance Requirements

Ties for use in open deck railway bridges should show signs of failure that are clearly visible to a bridge or track inspector wellin advance of total failure.

5.6.6 DESIGN VALIDATION TESTS (2012)

5.6.6.1 General

a. Prior to approval of alternative open deck bridge tie designs, the ties shall be subjected to testing for compliance with the recommendations of this chapter. The tests recommended herein shall be performed at testing facilities approved by the Engineer.


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b. Alternative bridge ties shall be subjected to the recommended acceptance tests. Failure of the bridge ties to pass the prescribed tests will be cause for rejection.

c. From a lot of not less than ten ties produced in accordance with the recommendations of this chapter, four ties will be selected at random by the engineer for laboratory testing. Each of four ties submitted for testing shall be carefully measured and examined to determine their compliance with the requirements of Article 5.6.3 Material (2012) and Article 5.6.4 General Requirements (2012). Upon satisfactory completion of this examination, two ties, which shall be known and identified as Tie “1” and “2”, shall be tested as recommended in paragraphs d and e below. The remaining two ties, which will be known and identified as Ties “3” and “4”, will be retained by the engineer for further test use and as a control for dimensional tolerances and surface appearance of ties subsequently manufactured.

d. All alternative material ties shall be subjected to the performance tests recommended in Article 5.3.3 with the exception of single tie lateral push testing (Section 2.9, Test 8). Note that Article 5.5.3 recommends performing additional tie performance tests as described in Part 2 of Chapter 30 as applicable. In addition, Article 5.5.3 highly recommends that a demonstration of field performance in actual track is accomplished before any large-scale purchase and installation of any given manufacturer’s composite ties.

e. Structural bridge ties loaded in bending shall be tested as recommended in Articles 5.6.6.2 and 5.6.6.3 below. This is not required for ties loaded in bearing only.

f. Alternative test methods may be used if approved by the Engineer.

5.6.6.2 Bending Deflection Test

Using a tie bending apparatus as shown in Figure 30-5-2, the minimum and maximum tie center deflection under loads of 27,000 lbs (120 kN) at each rail seat shall be as listed in Table 30-5-2. The 27,000 pound load is the design load without the factor of safety applied, rounded to the nearest thousand. Additional information for a suitable test rig is described in Reference 5.

The bending deflection test shall be carried out twice, at different load application rates:

a. Slow load application rate, The load shall be increased in such a way that the time to reach the 27,000 pounds is at least 20 minutes.

b. Higher load application rate. The load shall be applied so that 27,000 pounds is reached in 2-3 minutes.





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4A minimum deflection is recommended in an attempt to provide some of the beneficial properties of timber ties. The minimum deflection requirement helps to distribute axle loads to adjacent ties. It also provides attenuation properties that ensure thatimpacts generated on supporting members do not significantly exceed impacts on a structure with a standard wood tie.

Maximum recommended deflections are based on Chapter 7 guidelines of span length divided by 250, scaled for the ratio of test load to design load. Minimum recommended deflections are based on laboratory and field measurements of various timber ties1.

Alternative tie designs may provide the required deflection via means such as rail seat pads or other techniques.

Table 30-5-2. Tie Bending Deflection Requirements

Girder Spacing Minimum Deflection Maximum Deflection

7 foot (2134 mm) 0.11 in (2.8 mm) 0.33 in (8.4 mm)8 foot (2438 mm) 0.12 in (3.0 mm) 0.38 (9.7 mm)9 foot (2743 mm) 0.13 in (3.3 mm) 0.43 (10.9 mm)

1 Study conducted by the Transportation Technology Center, Inc., Pueblo, Colorado; project report to be published.

Figure 30-5-2. Tie Bending Test Apparatus


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5.6.6.3 Demonstration of Design Load Test

a. Design load test shall be performed using a test configuration comparable to that shown in Figure 30-5-2. Spacing of the reaction points should be the same as the intended center-to-center girder spacing (dimension a). Spacing of the load points shall be 60.0 inches (1524 mm) for standard gage track.

b. Sizes of plates for load and reaction points should be 12 inches (30 mm) in the direction of the longitudinal axis of the tie, by the full width of the tie.

c. Load shall be 53,000 lbs (240 kN) per rail.

d. The design load test shall be carried out twice, at different load application rates:

(1) Slow load application rate. The load shall be increased in such a way that the time to reach the 53,000 pounds is at least 20 minutes.

(2) Higher load application rate. The load shall be applied so that 53,000 pounds is reached in 2-3 minutes.

e. Any loss of integrity or inability to sustain the specified load must be considered a failure. Failures may include, but are not limited to, cracking, crushing, buckling, delamination, permanent distortion, and excessive deflection. Due to a wide variety of materials, design, and fabrication methods, failure modes will likely be different for various types of ties. Nevertheless any loss of integrity or inability to sustain the specified load must be considered a failure.

5.6.7 PRODUCTION QUALITY CONTROL OF ALTERNATE MATERIAL OPEN DECK BRIDGE TIES (2012)

After tie and rail fastening system have passed the tests in Article 5.6.6, Design Validation Tests (2012) and have been approved by the Engineer, further production of these items may proceed without further design testing. During production of such an approved design, quality-control tests must be performed to assure that at least 95 percent of the ties produced meet the design strength requirements. The quality-control tests must be acceptable to the Engineer.


30-6-1

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30, ParPart 6

Steel Ties

— 2012 —

TABLE OF CONTENTS


6.1 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-1

6.2 Physical & Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-1

6.3 Steel Switch Ties, Steel Grade Crossing Ties & Other Specialty Steel Ties . . . . . . . . . . . . . . . . . . . . . . . . 30-6-2

6.4 Ballast & Sub-Grade Requirement for Steel Ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-2

6.5 Tamping & Compaction of Ballast in Steel Tie Track & Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-3

6.6 Steel Tie Identification, Marking of Tie, Inspection and Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . 30-6-3


The information that follows provides basic guidelines for the design, selection, and use of steel crosstie systems.

SECTION 6.2 PHYSICAL & MECHANICAL PROPERTIES

a. General requirements for Steel Ties are as follows:

(1) Support the loads transmitted through the rails and transfer such loads to the ballast and sub-grade section of the roadbed.

(2) Steel ties should provide lateral and longitudinal track stability; while maintaining track surface, line, rail seat cant and rail gage.

(3) Shoulders for steel ties can be hook-in, welded-on, or other type of design that creates a permanent, fixed rail seat, to provide constant gauge and equilibrium of the rails in the track structure.


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(4) Steel tie shoulder design must be able to accept a variety of standard or specialty resilient fasteners to clamp the rail to the tie.

(5) Steel tie systems must be able to function in either non-insulated or insulated (signalized) applications as designed by the track engineer. Electrical isolation of the rail from steel ties in signalized applications must be provided by the fastening system with the use of insulating tie pads and insulators for elastic fastening devices.

(6) Steel tie designs may provide ballast inspection holes, as specified by end user and according to steel tie shape, which would allow for visual inspection of the tie underside to ensure that proper ballast tamping is achieved.

b. Steel ties are manufactured using ASTM A-242 steel, or equivalent, with a Corrosion Index of not less than 6.00 in accordance with ASTM G101: Legault-Leckie equation.

c. Steel ties can be made to a variety of design factors and cross shapes and to various lengths per the requirement of the track engineer. Tie widths normally fall between 10" to 12" in width.

d. Steel tie track design determines the optimal spacing between ties. The most common track spacings range from 20" to 24" tie center spacing. Spacing will depend upon track design, axle loads, curvature and maximum allowable ballast and sub-ballast pressure for given track structure.

e. Steel ties may be recyclable at the end of their service life.

SECTION 6.3 STEEL SWITCH TIES, STEEL GRADE CROSSING TIES & OTHER SPECIALTY STEEL TIES

a. Steel switch ties and other types of steel ties can be designed to be either non-insulated or insulated by use of the applicable fastener system components and proper care and maintenance thereof.

b. Steel ties used in grade crossing applications should use fastening devices coated/treated for corrosion to extend the life of the fasteners.

c. Steel ties can be coated with products designed to protect the tie and fastener system from corrosion and other caustic materials that may be transported over the track.

d. Steel bridge ties can be produced with our without guardrail protection.

SECTION 6.4 BALLAST & SUB-GRADE REQUIREMENT FOR STEEL TIES

Refer to Chapter 1, Roadway and Ballast, Part 2, Ballast for all ballast requirements.

In general, ballast type and depth of the track structure are key issues in track design when using steel track and switch ties.Increasing ballast depth will spread loads transmitted through the tie and ballast section over wider areas of the subgrade. Harder types of ballast, and those with high abrasion factors, will provide better drainage and support of steel ties than that of softer ballast types.

A minimum ballast section of at least 8" measured from the underside bearing surface of the tie is recommended for all types of track design using steel ties. AREMA Ballast Gradations 3, 4A and 4 are suitable for most steel tie mainline and secondary track applications, and AREMA Gradation 5 is better suited for yard track applications. AREMA Ballast Gradation 24 and 25 should be avoided for mainline/secondary use, as well as Gradation 57 for yard tracks.


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Engineers must insure that the track design does not overstress the ballast or sub-grade regardless of the tie type. Ballast material quality, tie center spacing, axle loads, train speed and track curvature are but some of the variables to consider whendetermining ballast pressure.

SECTION 6.5 TAMPING & COMPACTION OF BALLAST IN STEEL TIE TRACK & SWITCHES

Some steel ties may have less depth compared to that of wood, concrete, or other types of ties. It is therefore required that thetamping machine’s tools be raised accordingly before starting any tamping work in order to create proper ballast flow under the ties.

a. The center, middle section of all steel ties must be tamped in addition to the tie ends to fill the entire area under the tiewith ballast. Center tamping prevents ballast migration away from the railseat areas.

b. Some steel tie designs provide ballast inspection holes to permit visual inspection that the tie has been properly tamped.

c. Tamping machine work head limit switches must be properly adjusted before tamping steel ties to set the depth of insertion of the tamping tools. Check to ensure the top of work head tamping tools are 1/2" - 5/8" below the bottom edge of the steel tie in the squeeze position.

d. Steel tie track and switches can be built on top of the sub-grade surface or on pre-ballasted track surfaces.

e. When building steel tie track directly on top of the sub-grade, the initial surfacing raise for newly constructed track should exceed the height of the tamping tool face, or approximately 3", to avoid penetrating the sub-grade with tamping tools.

f. Final track alignment changes should be made before making the last surfacing pass and lift on steel tie track and switches.

SECTION 6.6 STEEL TIE IDENTIFICATION, MARKING OF TIE, INSPECTION AND QUALITY CONTROL

The manufacturer(s) of steel tie track ties, steel switch ties and other types of specialty steel ties will have a quality assuranceprogram in place to ensure products are manufactured according to the following minimum guidelines and specifications.

a. Manufacturer’s identification stamp, tie size, date of manufacture, and quality control code will be clearly and permanently marked on the top of each tie.

b. Develop and maintain a record keeping system to document inspection of incoming materials, finished parts and materials, and quality control inspections and tests.

c. Develop, institute and maintain a quality control inspection process; including same for test equipment, machinery, and tools used in the manufacturing process.

d. All manufacturing personnel responsible for quality control will have knowledge of required inspection and test procedures used in the process.

e. When requested, certification from the manufacturer will be furnished stating that steel ties were manufactured to meet this specification.


Ties





30-G-1

1

3

30

Chapter 30 Glossary1

— 2009 —The following terms are used in Chapter 30 Ties and placed here in alphabetical order for your convenience.

AbsorptionAmount of preservative taken up by, or forced into, timber during treatment. Generally expressed as gallons per cubic foot or gallons per cross tie or pounds per cubic foot.

Anti-Splitting DeviceAny device applied to the end or near the end of a tie or timber such as an anti-splitting iron, dowel or nail plate to reduce its splitting.

Bethell ProcessFull-cell pressure treatment of wood with any preservative solution in which initial vacuum is applied prior to preservative introduction into the cylinder.

BoredA tie which has had holes for spikes or for increased penetration of the preservative provided by passage through a machine designed for the purpose.

Borer, IncrementAn auger with a hollow shaft which as turned fills with a core of wood, which is extracted for determining the depth of penetration by a preservative, the width of the sapwood, the retention of preservative, or a physical characteristic or property of the sample.

Borers, MarineSmall marine insects which live in burrows or galleries which they excavate in wood submerged in sea water; principally Teredo, Bankia, Limnoria, Pholads and Sphaeroma.

Boulton Drying ProcessA process for drying wood by removing moisture from it by heating in preservatives under sufficient intensity of vacuum to evaporate water from the material at the temperature of the preservative used.

CompositeA material created by the combination of two or more materials (e.g., reinforcing elements in a matrix binder) to obtain specific characteristics and properties that are improved over those of the individual components. The resultant composite properties are usually some weighted average of the pure component properties. Composites are often classified on the

1 References, Vol. 83, 1982, p. 163.


Ties


30-G-2 AREMA Manual for Railway Engineering

basis of the form of the structure: laminar – composed of layers (e.g., wood laminates, plywood); particulate – the dispersed phase consists of small particles (i.e., “filled” plastic); fibrous – the dispersed phase consists of fibers (e.g., glass fiber reinforced composite); and combinations of the above forms.

Compressive StrengthThe maximum compressive stress (nominal) carried by a test specimen during a compression test. It may or may not be the compressive stress (nominal) carried by the test specimen at the moment of rupture.

CreepThe time-dependent deformation of a material under load. Creep is the strain occurring after the initial elastic deformation; also known as thermoplastic creep. Creep at room temperature is known as “cold flow.”

CreosoteAs used in wood preserving, creosote is a distillate of coal tar produced by high-temperature carbonization of bituminous coal; it consists principally of liquid and solid aromatic hydrocarbons, and contains appreciable quantities of tar acids and tar bases; it is heavier than water; and has a continuous boiling range of at least 125 degrees C and going to 400 degrees C beginning at about 200 degrees C.

Creosote-Coal Tar SolutionCreosote with coal tar added in prescribed proportions.

Creosote-Petroleum SolutionCreosote with petroleum added in prescribed proportions.

Cross TieThe transverse member of the track structure to which the rails are spiked or otherwise fastened to provide proper gage and to cushion, distribute, and transmit the stresses of traffic through the ballast to the roadbed.

Dating NailA nail with a head having a raised or depressed number or symbol which is driven into a longitudinal surface of a pile, pole, tie, or timber to identify the year in which the material was treated or installed.

DecayDisintegration of the wood substance due to the action of wood destroying fungi.

DelaminationThe separation of layers in an assembly because of failure of the adhesive, either in the adhesive itself or at the interface between the adhesive and the lamination.

Elastic LimitThe greatest stress that a material is capable of sustaining without permanent strain or deformation remaining after the complete release of the stress.

ElongationPercent increase in length of a material stressed by tension.


Glossary


AREMA Manual for Railway Engineering 30-G-3

1

3

4

Empty CellA treatment in which the cell walls in the treated portion of the wood remain coated with preservative, the cells being empty or only partially filled.

Engineered Composite TieA composite product designed and manufactured to function as a railroad cross tie.

FasteningA component or group of components of a track system which affixes the rail to the cross ties.

Fiber – For use in reinforced polymer products (FRP)A filament of high aspect ratio, typically with a very small cross-section, that may vary in length from short chopped strands to continuous lengths. Fiber for this purpose can be made of various materials (e.g., glass, graphite, and aramid).

Fiber-reinforced Polymer (FRP)A general term covering any type of polymer reinforced by fibrous glass or other fibers; also sometimes referred to as fiber-reinforced plastic.

Flexural Modulus (elastic)The ratio, within the elastic limit, of the outer fiber stress in a test specimen in flexure to the corresponding outer fiber strainin the specimen.

Flexure StrengthResistance to bending.

Full CellA treatment in which the cells in the treated portion of the wood remain either partially or completely filled with preservative.

FungiLow forms of plant life without roots, stems, or leaves, which contain no chlorophyll and derive nourishment from organic wood matter.

GroupingSorting forest products into groups according to their species, sapwood content, size, strength, and treatability.

HardwoodOne of the group of trees (deciduous) which have broad leaves. The term has no reference to the hardness of the wood.

HeartwoodInner core of the tree trunk comprising the annual rings containing non-living elements: usually darker in color than sapwood.

Heartwood TieA tie with sapwood no wider than one-fourth the width of the top of the tie between 20 in (50.8 cm) and 40 in (101.6 cm) from the middle of the tie.


Ties



IncisingPuncturing the longitudinal surfaces of poles, ties, and timbers to improve penetration by a preservative and/or to relieve surface tension as an aid in the control of checking.

InsertA device for securing an assembly and/or the rail to the tie. It may be cast in the tie at the time of manufacture or placed ina cored, cast or drilled hole in the tie.

InsulatorRail fastening component used to provide electrical insulation between the metallic surfaces of the clip, shoulder, and rail.

LaminateThe process of bonding laminations together with an adhesive. The laminating process includes materials preparation, application of the adhesive, assembly, application of glueline pressure, and curing of the adhesive.

Lateral LoadA load or component of a load at the gage corner of the rail parallel to the longitudinal axis of tie and perpendicular to the rail.

Longitudinal LoadA load or component of a load along the longitudinal axis of a rail.

Lowry ProcessAn empty cell process for treating wood with creosote in which there is injected, without a preliminary vacuum, an amount of creosote in excess of the required final retention, this excess then being removed by a quick high vacuum.

MatrixThe continuous material phase of a composite in which reinforcing fibers and/or fillers are embedded.

Moisture ContentAmount of moisture in wood, usually expressed as percentage of the dry weight of wood.

Negative BendingBending that produces tension or reduces compression in the top surface of the tie.

PenetrationThe depth to which preservative enters wood through both lateral or from an end surface.

PlasticA material that contains as an essential ingredient an organic substance of high molecular weight, built up from the repetition of chemical units. It is solid in its finished state and, at some stage during processing into finished articles, can be shaped by flow. Thermoplastic resins (e.g., polyethylene) can be remelted and reformed with the application of heat whereas thermosetting resins (e.g., epoxies) cannot be remelted once formed and hardened.


Glossary



1

3

4

PolymerA substance consisting of large molecules formed by combining many smaller molecules or monomers in a regular pattern. Examples of commonly used polymers include polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyurethane (PU).

Polymer Composite TieAn engineered composite tie that incorporates a polymer matrix as a primary component.

Positive BendingBending that produces tension or reduces compression in the bottom surface of the tie.

Post-tensioned Concrete TieA prestressed concrete tie using post-tension tendons to precompress concrete.

Post-tensioning TendonSteel strands, wires or bars which are stressed subsequent to placement and hardening of concrete.

Pressure ProcessA process in which pressure is applied in the treating cylinder to force preservatives into wood.

Prestressed TieA tie utilizing precompressed concrete and prestressing tendons.

Prestressed-Reinforced TieA reinforced concrete tie which, in addition to longitudinal reinforcing steel, uses prestressing tendons to resist bending butin which tension exceeding the modulus of rupture of the concrete may occur in the precompressed concrete under design loads. If cracks do occur, the resulting crack widths do not exceed specified values.

Prestressing TendonA strand, wire or bar designed to precompress the concrete.

Pretensioned Concrete TieA prestressed concrete tie using pretension tendons to precompress concrete.

Pretensioning TendonSteel strands, wires or bars which are stressed prior to the placement of concrete.

Rail SeatThe area of a tie on which rail rests.

Recycled PlasticPlastics composed only of post-consumer material or recovered material, or both, which may or may not have been subjected to additional processing or manufacturing steps such as recycled-regrind or reprocessed or reconstituted plastics. (ASTM D 883)


Ties



Reinforced Concrete TieA tie reinforced with deformed steel bars, welded wire fabric, deformed wire, or bar or rod mats and using non-precompressed concrete.

ReinforcementA comparatively high-strength or stiff material incorporated into another continuous material phase to increase the strength and/or stiffness of the resulting composite.

Reinforcement or Reinforcing SteelSteel, excluding prestressing tendons, introduced within a concrete tie to improve its structural strength, and to control deflection and cracking.

ResinIn a broad sense, the term is used to designate any polymer that is a basic material used for the manufacture of plastics, or asa component in adhesive systems.

Retention, FinalSee Absorption. Net.

Rueping ProcessAn empty, cell process for treating with creosote in which the following sequence is employed: Compressed air; cylinder filled without reducing pressure; pressure held until required absorption is obtained; final vacuum.

SapwoodOuter layers of growth in a tree, exclusive of bark, which contain living elements; usually lighter in color than heartwood.

Sapwood TieA tie with sapwood wider than one-fourth the width of the top of the tie between 20 inches (50.8 cm) and 40 inches (101.6 cm) from the middle of the tie.

Seasoning, AirEvaporation of moisture from wood by exposure to the atmosphere, in the open or under cover without artificial heat.

Shoulder and/or InsertA device that provides anchorage points within ties for rail fastening systems and other miscellaneous components. It may be cast in the tie at the time of manufacture or placed in a cored, cast or drilled hole in the tie.

Slabbed TieA tie sawed on top and bottom only. (Known also as “pole” tie and “round” tie).

SoftwoodOne of the group of trees (Conifers) which have needle-like or scale-like leaves. The term has no reference to the softness of the wood.

Spring Clip (or Clip)A rail fastening component that supplies a compressive load on the rail.


Glossary



1

3

4

Steam SeasoningPreparing green timber for treatment by subjecting it to the action of steam in a closed cylinder. Normally used for softwoods only.

Structural CrackA crack originating in the tensile face of the tie, extending to the outermost level of reinforcement or prestressing tendons and which increases in size under application of increasing load.

Substitute TieA tie of any material other than wood or of wood in combination with any other material.

Switch TieThe transverse member of the track structure which is longer than but functions as does the cross tie and in addition supports a crossover or turnout.

Tar, CoalThe nonaqueous portion of the liquid distillate obtained during the carbonization of bituminous coal.

Tie, AdzedA tie which has had the tie plate-bearing areas of its top made flat and smooth by passage through a machine designed for the purpose.

Tie PadRail fastening component used to separate tie and rail at the rails seat area.

Treat (verb)To apply preservative to wood.

Vertical LoadA load or component of a load at right angles to a line joining the two rail seats of the tie and normal to the longitudinal axisof the rail.

Weight UnitsTonnage refers to U.S. units of measure where 1 ton = 2 000 pounds, or where 1 tonne = 1 000 kilograms.

Wood PreservingThe art and science of protecting timber against the action of destructive agents. Usually refers to the treatment of wood with materials which prevent the attack of fungi, termites, marine borers, fire, etc.


Ties





30-R-1

1

3

1References

The following is a list of references used in Chapter 30, Ties and placed here in alphabetical order for your convenience.

1. Choros, J., B. Marquis and M. Coltman. 2007. Prevention of Derailments due to Concrete Tie Rail Seat Deterioration. In: Proceedings of the ASME/IEEE Joint Rail Conference and the ASME Internal Combustion Engine Division, SpringTechnical Conference, Pueblo, CO, March 2007, pp. 173-181.

2. Jimenez, R.,“Vertical Track Modulus in Plastic Composite Tie Test Zones at FAST,” Federal Railroad Administration, DOT/FRA/ORD-03/13, June 2003.

3. Kerr, A.D. and Bathurst, L.A. “Pads Ease Track Transitions”, Railway Track and Structures, August 2000.

4. Kerr, A.D., Fundamentals of Railway Track Engineering, Simmons-Boardman Books, Inc., 2003.

5. Kerr, A. D. and Moroney, B.E., “Track Transition Problems and Remedies,” Bulletin 742 -AREA, Vol. 94, Oct 1993.

6. Madsen, B., Sweeney, R.A.P., Shear Strength of Douglas Fir Timber Bridge Ties. Transportation Research Record: Journal of the Transportation Research Board, Volume 1691, pages 44-56, 1999.

7. Reiff, R. 2009. Evaluation of Concrete Tie Rail Seat Abrasion Detection/Measurement Systems, AAR Research Report RS-09-001, Washington D.C.

8. Sasaoka, C.D., Davis, D.D., Kock, K., Reiff, R.P., and GeMeiner, W., “Implementing Track Transition Solutions,”Technology Digest, January 2005.

9. Singh, S.P., Davis, D.D., Guillen, D., and Williams, D., “Reducing the Adverse Effects of Wheel Impacts on Special Trackwork Foundations,” Federal Railroad Administration, DOT/FRA/ORD-04/08, April 2004.

10. Zarembski, A., “Track transitions: The effect of changes in track stiffness”, Railway Track and Structures, June 1994, pp. 9-10.

11. Zeman, J.C., J.R. Edwards, D.A. Lange, and C.P.L. Barkan. 2012. Hydraulic pressure cracking in rail seats of concrete crossties. ACI Materials Journal 109 (6): 639-646.



30-R-2 AREMA Manual for Railway Engineering



30-A-1

1

3

30

Appendix

— 2014 —

TABLE OF CONTENTS


A-30-A-1 Crosstie Performance Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-2A-30-A-2 Design Qualification Specifications for Elastic Fasteners on Timber Cross Ties (2014) . . . . . . . . . . 30-A-14

LIST OF FIGURES


30-A-1 Uplift Test Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-1630-A-2 Longitudinal Rail Restraint Test Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-1730-A-3 Repeated Load Test Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-19

LIST OF TABLES


30-A-1 Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-330-A-2 Definitions and Comments for Table 30-A-1: Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-430-A-3 Rail Fastening Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-1030-A-4 Environmental Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-1030-A-5 Definitions and Comments for Table 30-A-3: Rail Fastening System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-1130-A-6 Test Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-1530-A-7 Repeated Load Cycle (See Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-A-18


Ties


30-A-2 AREMA Manual for Railway Engineering

30-A-1 CROSSTIE PERFORMANCE MATRIX

Section 30-A-1 Crosstie Performance Matrix of Chapter 30 is for information only and contains mechanical and environmental properties of crossties and their fastening systems. This representative information is segregated by the major tie types and includes concrete, wood, steel, and engineered composites.

Table 30-A-1 lists the mechanical properties of the tie. Table 30-A-3 contains mechanical properties of the tie and fastening system. Table 30-A-4 lists the environmental properties of the tie. Table 30-A-1 and Table 30-A-3 are supported by definitions and comments describing the values and calculations contained in the respective tables.


Appendix


AREMA Manual for Railway Engineering 30-A-3

Tabl

e 30

-A-1

. Mec

hani

cal P

rope

rtie

s


Ties



Tabl

e 30

-A-2

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-1:

Mec

hani

cal P

rope

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s

Cha

ract

eris

ticU

nit o

f Mea

sure

Def

initi

on

Col

umn

Hea

ding

D

escr

iptio

nN

. Mix

Hw

d= n

orth

ern

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, S. M

ix H

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ther

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ixed

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, SYP

= so

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tern

and

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ds,

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glas

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l: St

eel t

ies

of tr

ough

type

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mer

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iner

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nd h

ybri

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e de

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e La

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ate,

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ct. C

omp.

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e La

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ates

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, wid

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epth

2. V

olum

eC

ubic

feet

The

amou

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ied

by a

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) pag

e 35

4.3.

Den

sity

Poun

ds p

er cu

bic

foot

The

mas

s pe

r uni

t vol

ume

of a

sub

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ons

(1) p

age

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e W

ood:

The

val

ues

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e de

rive

d fr

om te

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43 a

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S Fo

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Ser

vice

dat

a. A

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l who

le ti

e va

lues

may

diff

er.

4. W

eigh

tPo

unds

The

forc

e ex

erte

d by

gra

vity

on

a bo

dy.

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the

prod

uct o

f the

mas

s of

the

body

an

d th

e ac

cele

ratio

n du

e to

gra

vity

(1) p

age

358.

5. M

omen

t of I

nert

iaIn

ches

4A

mea

sure

of t

he re

sist

ance

offe

red

by a

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y to

ang

ular

acc

eler

atio

n (1

) pag

e 22

.

Not

e C

oncr

ete:

The

rang

e of

val

ues

show

n in

Tab

le30

-A-1

incl

udes

cur

rent

de

sign

s fo

r tr

ansi

t rai

l tie

s. T

he fo

llow

ing

are

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imum

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ues

for

heav

y ha

ul

frei

ght:

Mom

ent o

f Ine

rtia

Sea

t= 3

70 in

ches

4

Cen

ter=

215

inch

es4


Appendix



6. S

ectio

n M

odul

usIn

ches

3Th

e ra

tio o

f the

mom

ent o

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of t

he cr

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reto

thegreatestdistan

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from

theneutrala

xis

(3) p

age

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Not

e C

oncr

ete:

The

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e of

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ues

show

n in

Tab

le30

-A-1

incl

udes

cur

rent

de

sign

s fo

r tr

ansi

t rai

l tie

s. T

he fo

llow

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are

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imum

val

ues

for

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y ha

ul

frei

ght:

Sect

ion

Mod

ulus

R

ail S

eat+

= 1

05 in

ches

3

R

ail S

eat-

= 1

00 in

ches

3

C

ente

r- =

75

inch

es3

C

ente

r+ =

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inch

es3

Tabl

e 30

-A-2

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-1:

Mec

hani

cal P

rope

rtie

s

Cha

ract

eris

ticU

nit o

f Mea

sure

Def

initi

on

Col

umn

Hea

ding

D

escr

iptio

nN

. Mix

Hw

d= n

orth

ern

mix

ed h

ardw

oods

, S. M

ix H

wd=

sou

ther

n m

ixed

ha

rdw

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, SYP

= so

uthe

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ello

w p

ine,

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eas

tern

and

wes

tern

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twoo

ds,

DF=

Dou

glas

fir.

Stee

l: St

eel t

ies

of tr

ough

type

des

ign.

Poly

mer

Com

posi

tes=

incl

udes

fibe

r, m

iner

al, a

nd h

ybri

d co

ncre

te/s

teel

rein

forc

ed

plas

tic ti

e de

sign

s.

Glu

e La

m.=

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e la

min

ate,

Dow

el L

am.=

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ate,

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ct. C

omp.

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ber.

= st

ruct

ural

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posi

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mbe

r.

Not

e La

min

ates

: A

ll va

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lam

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es a

re re

pres

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of d

ry s

ervi

ce.


Ties



7. M

odul

us o

f Ela

stic

ityPo

unds

per

squ

are

inch

It d

eter

min

es th

e st

ruct

ural

capa

city

of t

he cr

osst

ie a

nd is

impo

rtan

t for

trac

k lo

ad a

nd

defo

rmat

ion.

It i

s th

e m

easu

re o

f the

stif

fnes

s of

the

tie.

The

rela

tions

hip

betw

een

the

amou

nt a

cro

sstie

def

lect

s an

d th

e lo

ad c

ausi

ng th

e de

flect

ion

dete

rmin

es it

s st

iffne

ss

or M

OE

. Th

e cr

osst

ie is

sup

port

ed a

t bot

h en

ds w

hile

a co

ncen

trat

ed lo

ad b

ears

at t

he

cent

er.

Ela

stic

ity --

The

prop

erty

whe

reby

a b

ody,

whe

n de

form

ed b

y an

app

lied

load

, rec

over

s its

pre

viou

s co

nfig

urat

ion

whe

n th

e lo

ad is

rem

oved

. E

last

ic M

odul

us fo

r an

ela

stic

m

ater

ial,

the

ratio

of t

he s

tres

s to

the

resu

lting

str

ain

(1) p

age

111.

The

ratio

of t

he

unit

stre

ss to

the

unit

defo

rmat

ion

of a

stru

ctur

al e

last

ic m

ater

ial i

s a co

nsta

nt, a

s lon

g as

the

unit

stre

ss is

bel

ow th

e pr

opor

tiona

l lim

it (2

) pag

e 58

4.

Not

e C

oncr

ete:

Val

ues

are

base

d on

a 7

,000

psi

mix

. Th

is is

cal

cula

ted

acco

rdin

g to

th

e A

CI c

ode

and

will

diff

er fo

r di

ffere

nt c

oncr

ete

stre

ngth

s an

d/or

den

sitie

s.

Not

e W

ood:

The

val

ues

wer

e de

rive

d fr

om te

stin

g of

sm

all c

lear

spe

cim

ens

of w

ood

usin

g A

STM

pro

cedu

re D

-143

and

US

Fore

st S

ervi

ce d

ata.

Act

ual w

hole

tie

valu

es

may

diff

er.

Not

e P

olym

er C

ompo

site

s: M

OE

det

erm

ined

from

test

ing

who

le ti

e m

embe

rs in

ac

cord

ance

with

Par

t 2, T

est 1

C: B

endi

ng --

Cen

ter

Neg

ativ

e.

Not

e La

min

ates

: Glu

e La

m. M

OE

is e

stab

lishe

d ac

cord

ing

to A

STM

Inte

rnat

iona

l 37

37.

Stru

ctur

al C

ompo

site

Lum

ber

MO

E is

est

ablis

hed

usin

g A

STM

Inte

rnat

iona

l 545

6.

Tabl

e 30

-A-2

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-1:

Mec

hani

cal P

rope

rtie

s

Cha

ract

eris

ticU

nit o

f Mea

sure

Def

initi

on

Col

umn

Hea

ding

D

escr

iptio

nN

. Mix

Hw

d= n

orth

ern

mix

ed h

ardw

oods

, S. M

ix H

wd=

sou

ther

n m

ixed

ha

rdw

oods

, SYP

= so

uthe

rn y

ello

w p

ine,

Sof

twd=

eas

tern

and

wes

tern

sof

twoo

ds,

DF=

Dou

glas

fir.

Stee

l: St

eel t

ies

of tr

ough

type

des

ign.

Poly

mer

Com

posi

tes=

incl

udes

fibe

r, m

iner

al, a

nd h

ybri

d co

ncre

te/s

teel

rein

forc

ed

plas

tic ti

e de

sign

s.

Glu

e La

m.=

glu

e la

min

ate,

Dow

el L

am.=

dow

el la

min

ate,

Stru

ct. C

omp.

Lum

ber.

= st

ruct

ural

com

posi

te lu

mbe

r.

Not

e La

min

ates

: A

ll va

lues

for

lam

inat

es a

re re

pres

enta

tive

of d

ry s

ervi

ce.


Appendix



8. M

odul

us o

f Rup

ture

Poun

ds p

er s

quar

e in

chIt

mea

sure

s the

stru

ctur

al b

reak

age

of th

e cr

osst

ie a

nd is

impo

rtan

t for

trac

k lo

ad

capa

city

and

sur

faci

ng.

The

MO

R in

ben

ding

refle

cts

the

max

imum

load

carr

ying

ca

paci

ty o

f a c

ross

tie a

nd is

pro

port

iona

l to

the

max

imum

mom

ent b

orne

by

a cr

osst

ie.

It is

als

o an

acc

epte

d cr

iteri

on fo

r str

engt

h.

The

max

imum

str

ess

per u

nit a

rea

that

a s

peci

men

can

with

stan

d w

ithou

t br

eaki

ng w

hen

it is

ben

t, as

cal

cula

ted

from

the

brea

king

load

und

er th

e as

sum

ptio

n th

at th

e sp

ecim

en is

ela

stic

unt

il ru

ptur

e ta

kes

plac

e (3

) pag

e 63

7.

Not

e C

oncr

ete:

Val

ues

are

base

d on

a 7

, 000

psi

mix

. Th

is is

cal

cula

ted

acco

rdin

g to

the

AC

I cod

e an

d w

ill d

iffer

for

diffe

rent

con

cret

e st

reng

ths

and/

or

dens

ities

.

Not

e W

ood:

The

val

ues

wer

e de

rive

d fr

om te

stin

g of

sm

all c

lear

spe

cim

ens

of

woo

d us

ing

AST

M p

roce

dure

D-1

43 a

nd U

S Fo

rest

Ser

vice

dat

a. A

ctua

l who

le ti

e va

lues

may

diff

er.

Not

e P

olym

er C

ompo

site

s: M

OR

det

erm

ined

from

test

ing

who

le ti

e m

embe

rs

in a

ccor

danc

e w

ith P

art 2

, Tes

t 1C

: Ben

ding

-- C

ente

r N

egat

ive.

Not

e La

min

ates

: G

lue

Lam

. MO

R is

est

ablis

hed

acco

rdin

g to

AST

M 3

737.

Stru

ctur

al C

ompo

site

Lum

ber M

OR

is e

stab

lishe

d us

ing

AST

M 5

456.

Tabl

e 30

-A-2

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-1:

Mec

hani

cal P

rope

rtie

s

Cha

ract

eris

ticU

nit o

f Mea

sure

Def

initi

on

Col

umn

Hea

ding

D

escr

iptio

nN

. Mix

Hw

d= n

orth

ern

mix

ed h

ardw

oods

, S. M

ix H

wd=

sou

ther

n m

ixed

ha

rdw

oods

, SYP

= so

uthe

rn y

ello

w p

ine,

Sof

twd=

eas

tern

and

wes

tern

sof

twoo

ds,

DF=

Dou

glas

fir.

Stee

l: St

eel t

ies

of tr

ough

type

des

ign.

Poly

mer

Com

posi

tes=

incl

udes

fibe

r, m

iner

al, a

nd h

ybri

d co

ncre

te/s

teel

rein

forc

ed

plas

tic ti

e de

sign

s.

Glu

e La

m.=

glu

e la

min

ate,

Dow

el L

am.=

dow

el la

min

ate,

Stru

ct. C

omp.

Lum

ber.

= st

ruct

ural

com

posi

te lu

mbe

r.

Not

e La

min

ates

: A

ll va

lues

for

lam

inat

es a

re re

pres

enta

tive

of d

ry s

ervi

ce.


Ties



Tabl

e 30

-A-2

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-1:

Mec

hani

cal P

rope

rtie

s


Appendix



Tabl

e 30

-A-2

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-1:

Mec

hani

cal P

rope

rtie

s


Ties



Tabl

e 30

-A-3

. Rai

l Fas

teni

ng S

yste

ms

Tabl

e 30

-A-4

. Env

ironm

enta

l Pro

pert

ies


Appendix



Tabl

e 30

-A-5

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-3:

Rai

l Fas

teni

ng S

yste

m

Con

cise

Dic

tiona

ry o

f Phy

sics

The

Inte

rnat

iona

l Dic

tiona

ry o

f Phy

sics

and

Ele

ctro

nics

Dic

tiona

ry o

f Phy

sics

and

Mat

hem

atic

s

AST

M A

nnua

l Boo

k of

Sta

ndar

ds


Ties



Tabl

e 30

-A-5

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-3:

Rai

l Fas

teni

ng S

yste

m

Con

cise

Dic

tiona

ry o

f Phy

sics

The

Inte

rnat

iona

l Dic

tiona

ry o

f Phy

sics

and

Ele

ctro

nics

Dic

tiona

ry o

f Phy

sics

and

Mat

hem

atic

s

AST

M A

nnua

l Boo

k of

Sta

ndar

ds


Appendix



Tabl

e 30

-A-5

. Def

initi

ons

and

Com

men

ts fo

r Tab

le 3

0-A

-3:

Rai

l Fas

teni

ng S

yste

m

Con

cise

Dic

tiona

ry o

f Phy

sics

The

Inte

rnat

iona

l Dic

tiona

ry o

f Phy

sics

and

Ele

ctro

nics

Dic

tiona

ry o

f Phy

sics

and

Mat

hem

atic

s

AST

M A

nnua

l Boo

k of

Sta

ndar

ds


Ties



30-A-2 DESIGN QUALIFICATION SPECIFICATIONS FOR ELASTIC FASTENERS ON TIMBER CROSS TIES (2014)1

The content in this Appendix was transferred from Chapter 5, Part 9 Design Qualification Specifications for Elastic Fasteners on Timber Cross Ties to Chapter 30, Appendix 30-A-2, to appropriately integrate these tests into the tie and fastener qualifications tests located in Chapter 30. A review is underway to merge this content.

This specification is intended to provide necessary guidance to qualify the design of an Elastic Rail Fastener system for use ina mainline railway track with wood cross ties. These are minimum requirements; products qualifying under this specification may not perform acceptably where vehicle loading exceeds conventional 100 ton (rated) loads or where curvature or grade are more severe than that in general practice.

Individual components within a qualifying system are not necessarily qualified when used in a different system of components. Modifications to a qualifying system, either in components, geometry, materials or manufacturing procedures are grounds for requiring re-qualification under this specification.

30-A-2.1 DEFINITIONS (2014)

30-A-2.1.1 Terms

The following terms are for general use in this part. Specialized terms appear in individual articles. Refer to the Glossary located at the end of the chapter for definitions.

30-A-2.2 GENERAL REQUIREMENTS (2014)

30-A-2.2.1 Submittals

Fastener systems for qualification testing under this specification shall be submitted with the following documentation prior toinitiation of qualifying testing:

1 References, Vol. 94 (1994), p. 86.

Cross Ties Rail Fastener (This specification only addresses wood tie supports.)

Elastic Clip - Resilient Rail Fastener

Elastic Rail Fastener - Elastic Fastener

Engineer Rail Seat

Hold Down Device Rigid Clip

Lateral Load Track Modulus

Longitudinal Load Veritical Load

Rail Clip


Appendix



1

3

4

a. Drawings of the assembly and each component including mating plates, spikes, screws, etc., by others;

b. Bills of material listing part/component identification;

c. General description of materials used in each component identified in the assembly drawings;

d. Manufacturing tolerance, including mating tolerances among system components and the rail;

e. Identification of special conditions such as at rail joints and other special applications where the submitted design may not apply.

30-A-2.2.2 Minimum Acceptance

All fasteners tested, with the exception of those special conditions identified in Paragraph 30-A-2.2.1e, shall provide minimum functional performance stated by all articles of this specification through the full range of tolerances of all mating componentsincluding rail and ties as shown on the submitted drawings.

30-A-2.2.3 Qualification Test Facility

Sampling, testing and reporting shall be conducted by a laboratory, institution or agency approved by the Engineer.

30-A-2.2.4 Fastener Profile

In principle, the fastener system should have a profile which clears the silhouette of all operating and maintenance equipment intended for use on the track.

30-A-2.3 LABORATORY QUALIFYING TESTS (2014)

30-A-2.3.1 Test Configuration

a. The test configurations shall be as specified by each test sequence.

b. The standard tie for qualification testing under this specification is a new dried wood tie of the Southern Yellow Pine species, AREMA Grade 5 in cross section, and no less than 42.5 inches length. The centerline of the test rail shall be placed no less than 18.25 inches and no more than 21.25 inches from the end of the tie.

30-A-2.3.2 Sampling

A minimum of 10 complete assemblies shall be selected by the responsible testing agency from a lot of individual components which are representative of production-run components. A minimum of two full assemblies shall then be chosen as test assemblies. All selected test assemblies shall be subjected to the full battery of testing under this specification.

30-A-2.3.3 Test Sequence

The test procedures are provided in the following subarticles. The test sequence for each system is found in Table 30-A-6.

Table 30-A-6. Test Sequence

Sequence Test DescriptionArticle

Reference

1. Uplift Test 30-A-2.3.42. Longitudinal Restraint Test 30-A-2.3.5


Ties



30-A-2.3.4 Uplift Test

a. The uplift test shall be the test configuration shown in Figure 30-A-1.

b. With the tie rigidly fixed to the load frame, a load shall be applied to the rail through the vertical rail centerline, perpendicular to the rail seat, in the direction away from the tie. Simultaneously, the vertical deflection of the rail relative to the load frame and separately, the tie plate relative to the load frame, and the vertical position of the hold-down devices relative to the tie, shall be measured. Prior to qualification runs, the system will be “bedded in” using 1,000 cycles vertical load from –3,000 to +3,000 pounds. Torque adjustment or re-driving components after bedding-in is not permitted. All measurements shall be zeroed after bedding-in which shall then be the initial condition.

c. All measurements shall be taken to a load of 8,000 pounds, with data permanently recorded every 500 pounds. The load shall then be released with all measurements being recorded as in the load application cycle.

d. The fastener system shall be rejected if, during any one test run:

(1) The rail separates more than 0.050 inch from the tie;

3. Repeated Load Test 30-A-2.3.64. Uplift Test (repeat #1) 30-A-2.3.45. Longitudinal Restraint Test (repeat #2) 30-A-2.3.56. Rotational Restraint 30-A-2.3.7

Table 30-A-6. Test Sequence

Sequence Test DescriptionArticle

Reference

Figure 30-A-1. Uplift Test Configuration


Appendix



1

3

4

(2) The tie plate is displaced more than 0.030 inch from the “seated-in” position after unloading;

(3) The rail base vertical deflection after unloading is greater than 0.010 inch;

(4) The hold-down devices uplift more than 0.030 inch from initial conditions any time during the load cycle.

e. The fastener system and its components shall be inspected under full load conditions and after unloading for separation or damage relevant to the particular design under test.

f. Load versus deflection curves shall be plotted for every run as test documentation.

30-A-2.3.5 Longitudinal Rail Restraint

The longitudinal rail restraint test includes testing under static and dynamic load conditions. The longitudinal rail restraint test shall be the test configuration in Figure 30-A-2 for both load conditions.

30-A-2.3.5.1 Static Longitudinal Load Test

a. With the standard tie rigidly fixed to the load frame in the vertical plane and along the longitudinal rail axis, pre-apply 1,000 pounds, longitudinal load to a point within 3/8 inch of the rail base, while measuring the longitudinal deflection of the rail relative to the tie (or load frame) and, separately, the tie plate relative to the load frame.

b. The applied longitudinal load and resulting longitudinal deflections of the rail relative to the tie plate shall be measured at every 500 pound increment of longitudinal load. The load shall continue to be applied until the rail slips longitudinally 1/2 inch through the fastener. After the rail longitudinal slip occurs with a 1/2 inch longitudinal measured deflection, the load shall be released and the rail longitudinal deflection shall be recorded. If the post-load longitudinal deflection differs from that at the final full load, the testing agency shall report the reasons for the difference in post-loading deflection readings such as tie rotation, visible deflection of tie plate relative to tie, etc.

Figure 30-A-2. Longitudinal Rail Restraint Test Configuration


Ties



c. The fastener system shall be rejected if, during any one test run, the rail slips continuously in the longitudinal direction more than 1/2 inch at less than 4,800 pounds.

d. Longitudinal load versus longitudinal deflection shall be plotted for every run as test documentation.

30-A-2.3.5.2 Dynamic Longitudinal Load Test

a. With the standard tie rigidly fixed to the load frame in the vertical plane and along the longitudinal rail axis, pre-app1y 1,000 pounds longitudinal load to a point within 3/8 inch of the rail base, while measuring the longitudinal deflection of the rail relative to the tie (or load frame) and, separately, the tie plate relative to the load frame. During the longitudinal load application, a vertical vibration of 1,000 pounds (peak to peak) at a frequency of 15 Hz (±2 Hz) shall be applied through the rail at the mid-point between ties.

b. The applied longitudinal load and resulting longitudinal deflections of the rail relative to the tie plate shall be measured every 500 pounds of longitudinal load. The load shall continue to be applied until the rail slips longitudinally 1/2 inch through the fastener. After the rail longitudinal slip occurs with a 1/2 inch longitudinal measured deflection, the load shall be released and the rail longitudinal deflection shall be recorded. If the post-load longitudinal deflection differs from that at the final full load, the testing agency shall report the reasons for the post-loading difference in deflection readings such as tie rotation, visible deflection of tie plate, etc.

c. The fastener system shall be rejected if, during any one test run, the rail slips continuously in the longitudinal direction more than 1/2 inch at less than 4,000 pounds.

d. Longitudinal load versus longitudinal deflection shall be plotted for every run as test documentation.

30-A-2.3.6 Repeated Load Test

a. The repeated load test shall be the test configuration shown in Figure 30-A-3.

b. With the ties rigidly fixed to the load frame, vertical and lateral loads shall be applied for 3 million cycles in the sequence shown in Table 30-A-7.

Table 30-A-7. Repeated Load Cycle(See Note 1)

StepVertical Load

(lb)Lateral Load

(lb)

1 0 02 –3,000 03 42,000 04 42,000 21,0005 21,000 13,0006 0 3,0007 0 –3,000

Note 1: Steps 1 through 7 represent one load cycle; this sequence shall be repeated for the number of load cycles specified.Each step in the load sequence shall have the same time duration.Positive vertical loads are downward through the rail head, fastener and tie, illustrated in Figure 30-A-3.Positive lateral loads are applied at the gage side of the rail towards the field side.Rail base deflection measurements shall be placed within 1/4 inch of the rail base edge.


Appendix



1

3

4

c. The measurements shall include but not be limited to:

(1) Vertical load.

(2) Lateral load.

(3) Lateral rail head deflection.

(4) Lateral rail base deflection.

(5) Vertical deflection at each edge of the rail base relative to the tie.

d. Measurements shall be conducted during the first ten cycles of loading (with all instrumentation adjusted to zero values before first load). Measurements shall then be conducted during ten load cycles after every 300,000 load cycles (±50,000 cycles).

e. The testing agency shall record any tightening of bolt or screw components during the repeated load test. This documentation shall include a description of the tightening or adjustment made and the number of load cycles at which the adjustment was done.

f. The fastener system shall be rejected if:

Figure 30-A-3. Repeated Load Test Configuration


Ties



(1) Any component fails.

(2) Vertical or lateral permanent deflection exceeds 1/16 inch (relative to the load frame) more than the system tolerance, such as rail-to-plate lateral shoulder clearance.

(3) The maximum lateral deflection of the rail head is 1/8 inch at any time during the test.

(4) A Purchaser considers the amount or frequency of system adjustments to be excessive.

g. Minimum test documentation shall include all measured date (loads and deflections) from each periodic measurement sequence.

30-A-2.3.7 Rotational Restraint

a. Using the final test configuration (the second longitudinal resistance test), the rail shall be loaded laterally (i.e. parallelto the tie) at the rail head while measuring the rail base lateral deflection and the vertical deflection at both rail base edges.

b. No vertical load shall be applied during this sequence.

c. After a lateral load of 1,000 pounds is applied to take up all lateral tolerance, the deflection measurements shall be set to zero. The three deflections shall be measured at lateral load increments of 1,000 pounds to a maximum of 4,000 pounds or a deflection greater than 0.100 inch, whichever occurs first. This test sequence shall be completed in not less than one minute.

d. The lateral load shall then be returned to zero, followed by final deflection measurements.

e. The fastener system shall be rejected if any component fails (breaks, permanently deforms to an unserviceable condition) within the 4,000 pound load limit, or a deflection greater than 0.100 inch occurs at a lateral load less than 4,000 pounds.


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