tmc 311 transoms - transport for nsw · engineer civil or chief engineer track as appropriate. c4-2...

Owner: Chief Engineer Civil

Approved by: John Stapleton A/Principal Engineer Technology & Standards

Authorised by: Richard Hitch Chief Engineer Civil

Disclaimer This document was prepared for use on the RailCorp Network only. RailCorp makes no warranties, express or implied, that compliance with the contents of this document shall be sufficient to ensure safe systems or work or operation. It is the document user’s sole responsibility to ensure that the copy of the document it is viewing is the current version of the document as in use by RailCorp. RailCorp accepts no liability whatsoever in relation to the use of this document by any party, and RailCorp excludes any liability which arises in any manner by the use of this document. Copyright The information in this document is protected by Copyright and no part of this document may be reproduced, altered, stored or transmitted by any person without the prior consent of RailCorp

of 25 UNCONTROLLED WHEN PRINTED

Engineering Manual Structures

TMC 311

TRANSOMS

Version 1.1

Issued July 2010

Engi

neer

ing

Man

ual

RailCorp Engineering Manual — Structures Transoms TMC 311

© Rail Corporation of 25 Issued July 2010 1.1 UNCONTROLLED WHEN PRINTED Version

Document control Revision Date of Approval Summary of change

1.1 Changes detailed in Summary table below

1 November 2009 First issue as a RailCorp document

Summary of changes from previous version Chapter Current Revision Summary of change

Control Pages

1.1 Update version details

1.0 1.1 2.0 1.1 3.0 1.1 4.0 1.0 C4-6.3: change lock nuts from steel zinc plated to plastic 5.0 1.0

App 1 1.0


© Rail Corporation of 25 Issued July 2010 1.1 UNCONTROLLED WHEN PRINTED Version

Contents Chapter 1 General....................................................................................................................................... 4

C1-1 Purpose....................................................................................................................................... 4 C1-2 Context........................................................................................................................................ 4 C1-3 How to read this Manual ............................................................................................................. 4 C1-4 References.................................................................................................................................. 4 C1-5 Definitions, abbreviations and acronyms .................................................................................... 5

Chapter 2 Management Requirements ..................................................................................................... 6 Chapter 3 Competencies............................................................................................................................ 7 Chapter 4 Planning and Preparation ........................................................................................................ 8

C4-1 General ....................................................................................................................................... 8 C4-2 Programming of work.................................................................................................................. 8 C4-3 Technical considerations ............................................................................................................ 8 C4-4 Survey ......................................................................................................................................... 9 C4-5 Transoms .................................................................................................................................... 9 C4-6 Transom fastening systems ...................................................................................................... 13

Chapter 5 Installation ............................................................................................................................... 17 C5-1 General ..................................................................................................................................... 17 C5-2 Site storage of materials ........................................................................................................... 17 C5-3 Removal of existing transoms................................................................................................... 17 C5-4 Transfer of transom bolts to outer flange.................................................................................. 17 C5-5 Preparation of girder flanges..................................................................................................... 18 C5-6 Installation of new transoms on a face ..................................................................................... 18 C5-7 Installation of individual transoms............................................................................................. 20 C5-8 Cleaning up...............................................................................................................................22

Appendix 1 Typical Transom Assemblies ................................................................................................ 23


© Rail Corporation of 25 Issued July 2010 UNCONTROLLED WHEN PRINTED Version 1.1

Chapter 1 General C1-1 Purpose

This manual provides requirements, processes and guidelines for the installation and maintenance of transoms on underbridges.

The manual applies to both new structures and the replacement of transoms that have reached the end of their life on existing structures.

The document applies to transoms made of timber material only. It does not apply to alternative materials that may be developed or approved in the future.

Installation and maintenance of rail fastenings shall be in accordance with TMC 231 – Sleepers & Fastenings.

C1-2 Context The manual is part of RailCorp's engineering standards and procedures publications.

More specifically, it is part of the Civil Engineering suite that comprises standards, installation and maintenance manuals and specifications.

Manuals contain requirements, processes and guidelines for the management of structures, geotechnical and right of way assets and for carrying out examination, construction, installation and maintenance activities.

The manual is written for the persons undertaking installation and maintenance activities.

It also contains management requirements for Civil Maintenance Engineers and Team Managers needing to know what they are required to do to manage transom installation on their area, and project managers needing to know what they are required to do to manage the renewal activity their teams are undertaking.

C1-3 How to read this Manual When you read this Manual, you will not need to refer to RailCorp Engineering Standards.

Any requirements from the Standards have been included in the sections of the Manual and shown shaded. The shaded sections are extracts from RailCorp Standard ESC 310 “Underbridges” unless otherwise noted.

The best way to find information in the manual is to look at the Table of Contents starting on page 2. Ask yourself what job you are doing? The Table of Contents is written to reflect work activities.

When you read the information, you will not need to refer to RailCorp Engineering standards. Any requirements from standards have been included in the sections of the manual and shown like this:

The following design requirements are extracted from RailCorp Standard ESC 310

Timber transoms are to be 250mm wide and have a minimum length of 2800mm. The spacing should not exceed 600mm.

Reference is however made to other Manuals.

C1-4 References AS 1111.1 - 2000 ISO metric hexagon bolts and screws – Product grade C Part 1: Bolts

AS 1112.3 - 2000 ISO metric hexagon nuts Part 3: Product grade C

AS 1214 -1983 Hot-dip galvanised coatings on threaded fasteners (ISO metric coarse thread series)



AS 1252 - 1996 High strength steel bolts with associated nuts and washers for structural engineering

AS 3818.1 - 2003 Timber – Heavy structural products – Visually graded, Part 1: General requirements

AS 3818.2 - 2004 Timber – Heavy structural products – Visually graded, Part 2: Railway track timbers

AS 4100 - 1998 Steel structures

SPC 311 - Timber Transoms

TMC 001 - Civil Technical Competencies and Engineering Authority

TMC 203 - Track Inspection

TMC 211 - Track geometry & Stability

TMC 221 - Rail Installation and Repair

TMC 222 - Rail Welding

TMC 223 - Rail Adjustment

TMC 231 - Sleepers & Fastenings

TMC - 304 Structures Construction

TMC 305 - Structures Assessment

C1-5 Definitions, abbreviations and acronyms Transom: Structural member (usually timber) laid across girders for

attachment of rails and guard rails on transom top spans.

Failed / missing transoms:

Are those that are broken, missing or do not give vertical support to the rails.

Effective transoms: Transom/fastener system where the required fastenings are in place and which provides vertical support and lateral restraint. Restraint must allow no lateral movement of the fastenings relative to the transom. The transom must provide gauge restraint and must be one piece that will not separate along its length or transversely.

Transoms must have a flat rail plate seat.

Transoms may not have more than 20% loss from any part.

A transom that can be re-drilled will become effective again. It must have sufficient material between the rail fastenings (in the “four foot”) to distribute the load adequately.

Ineffective transoms:

Transom that is not effective. Transoms with rot or holes through which “daylight” can be seen are not satisfactory.

Includes those that are missing or failed.



Chapter 2 Management Requirements Civil Maintenance Engineers must establish systems to ensure:

− installation of transoms is done in accordance with the requirements of this manual and by people with the appropriate competencies

− certification of transom installation is done by people with the appropriate competencies.



Chapter 3 Competencies NOTE: These competencies may enable activities to be carried out in other manuals. For a comprehensive list of all activities that are covered by a given competency see Engineering Manual TMC 001 – Civil Technical Competencies and Engineering Authority.

To carry out this work

You need these competencies

Remove and install transoms

Install and replace bridge transoms (To be developed)

Remove and install sleeper plates, pads and insulators

TDT X04 – Replace railway sleepers

AND TDT X09 - Install and maintain rail anchoring and fastening systems

Rebore and regauge transoms

TDT X04 – Replace railway sleepers

AND TDT X09 - Install and maintain rail anchoring and fastening systems

Restore ballast profile after retransomming

TDT X03 – Undertake track ballast activity

Remove and install rails

TDT X05 – Install and replace rail

Remove and install guard rails

TDT B36 – Install and maintain guard and check rails

Weld rails TDT W4 – Weld using aluminothermic welding technique

Adjust rails TDT B61 – establish and maintain correct rail stress

Certify track safe during or after installation of transoms

Install and replace transoms (To be developed)

AND TDT B38 – Maintain track geometry

Certify structure safe after installation of transoms

Install and replace transoms (To be developed)

AND Assess structures (To be developed)



Chapter 4 Planning and Preparation C4-1 General

When planning to replace transoms on existing bridges, the Civil Maintenance Engineer shall consider the following aspects:

− Whether train axle loadings have increased or are likely to increase in the near future (e.g. during the estimated life of the transoms). If this is the case, reference should be made to the Chief Engineer Civil for guidance as to whether the transoms should be increased in size;

− Whether it would be more cost-effective or appropriate to eliminate the timber transoms, either by way of the use of alternative materials or by conversion of the bridge top to a ballasted or direct-fix configuration. Reference should be made to the Chief Engineer Civil for advice if re-configuration is being considered.

− Whether the opportunity should be taken to re-grade the track over the bridge or to increase the track centres where there is more than one track on the bridge. On bridges with curved track, the opportunity is also presented to adjust the super-elevation of the track if required. If re-grading and/ or re-alignment are being considered, advice should be sought from the Chief Engineer Civil or Chief Engineer Track as appropriate.

C4-2 Programming of work Most programmes for the replacement of transoms on existing bridges are based on total replacement on a face (i.e. all transoms in a span or bridge) in planned track possessions. The timber transoms should be procured 2 to 3 years in advance of their planned installation, to allow time for seasoning (see Section 4-5.3).

Each work programme should be carefully planned and documented including those activities (preparatory work) that can be undertaken in advance of the possession and clean-up works following the end of the possession.

Work programme should include assessment of:

− Requirement for use of vibration isolation fastenings on the transoms and sleepers on the bridge approach for bridge end treatment

− Upgrading of guard rails including insulation.

The programming must also include other resources that may be required such as track adjusting and welding staff.

C4-3 Technical considerations Consider the key technical risks of undertaking retransomming work. This includes:

− Incorrect gauge after the work

− Top, twist, line and/or superelevation defects after the work

− Transoms or equipment foul during work

− Site obstructions

− Site access for the delivery of materials and equipment

− Transom spacing

− Transom support (packing) and fastenings

− Possible disturbance to red lead coating on existing steelwork

− Track stability especially during summer months (See RailCorp Engineering Manual TMC 211 – Track Geometry & Stability)

− Rail fastenings, sleeper plates

− Incorrect clip type shorting out insulated joints



− Shorting out insulated joints (eg sleeper plates, fastening, scrap left behind)

− Ballast condition and profile

− Trains tripping on high ballast at bridge ends

− Ballast fouling points operation

− Damage to trackside signal equipment (bondwire, potheads, train trip arms), from material placement or movement, transom insertion and removal equipment

− Damage to train monitoring equipment (See TMC 211).

C4-4 Survey One of the key steps in preparing for the replacement of transoms on an existing bridge is to arrange for a detailed survey to be undertaken of the existing bridge and track. The survey should pick up:

− The position of the overhead wiring relative to the track

− The alignment of the existing track/s

− The existing track centres

− The existing rail levels

− The existing track superelevation (if on a curve)

− The precise location of the holding-down bolts.

The level of the rails and girders supporting the transoms on existing bridges may vary for the following reasons:

− The bridge is on a transition or full horizontal curve with varying super-elevation

− The bridge is on a vertical curve (e.g. No.1 span on the Nepean River bridge)

− The top flanges of the girders have irregular surfaces, generally associated with the original fabrication

− The main bridge girders have a longitudinal camber that has been deliberately applied during fabrication to offset deflections under live traffic.

For these reasons, the detailed survey should also pick up the levels and position of the existing girder supporting flanges.

If the track is to be re-aligned (see Section C4-1 above), the direction of the Civil Maintenance Engineer should be sought as to whether it would be preferable to move the bridge girders and bearings rather than offset the track to the girders, which may introduce additional bending in the transoms and girder flanges.

Following finalisation of the rail levels and alignments on the proposed new transoms, the transoms should then be designed to achieve a smooth final rail level under the dead load condition, with the following exceptions:

− Where there this a designed vertical curve on the bridge

− Where there is superelevation on the bridge.

The above conditions may be achieved either by individual thicknessing of the transoms (see Section C4-5.5 below) or by the use of transom packers of varying thicknesses.

Transom packers shall be used to provide super-elevation on bridges in preference to notching of transoms.

C4-5 Transoms C4-5.1 General

Identify transoms to be removed.



If traffic will operate over the track before the retransomming is completed, plan the work so that the track will remain tied in accordance with the operating limits for sleeper condition in TMC 203 – Track Inspection. DO NOT unfasten and remove more transoms than can be tied in the available time.

Check the length of existing transoms.

C4-5.2 Transom sizes Timber transoms are to be ordered and supplied in accordance with Engineering Specification SPC 311 “Timber Transoms”.


Timber transoms are to be 250mm wide and have a minimum length of 2800mm. The spacing should not exceed 600mm.

Table 1 below gives the minimum thickness of transoms (measured at any point along the length of the transom), based on:

− Design loading of 300LA + DLA

− Track speed of 115 km/h

− Timber stress grade of F22 (Strength Group 2) in accordance with AS 3818.2

− Timber joint strength of J1

− Holding down bolt size M30

Girder centres spacing

(mm)

Transom spacing

(mm)

Horizontal alignment of track

(Radius m)

Minimum transom

thickness

(mm)

> 800 170 500 - 550

< 800 200

> 800 190

2000

600

< 800 210

> 800 190 500 - 550

< 800 220

> 800 200

2100

600

< 800 220

Table 1

Adjustments to the above minimum thicknesses are to be made if different stress grades and joint strengths of timber are used.

Special approval may be given by the Chief Engineer Civil for thinner transoms to be used where restricted clearances exist (such as electrified track on a through truss underbridge). This approval may impose additional inspection and maintenance requirements.

Track offsets from span centreline > 70mm are not permitted without approval of the Chief Engineer Civil.

For each bridge, the transoms should all be of an equal length.

Homogeneity of timber species should be maintained in each structure.



For new underbridges, the thickness and spacing of the transoms will be specified by the designer and shown on the bridge drawings.

For existing underbridges, standard transom top steel span drawings since 1980 have shown transoms to be from 160 mm to 165 mm nominal thickness. Many prior installations however have transoms 150 mm thick and sometimes less.

Table 1 gives the minimum thickness of transoms to be used when replacing life-expired transoms on existing structures. The minimum thickness is to apply at any point along the length of the transom and is based on normal main line track loading and full main line speed:

Adjustments may also be made for bridges carrying less than normal main line loads or full main line speed. In both instances, reference should be made to the Chief Engineer Civil for advice on minimum thicknesses.

C4-5.3 Seasoning of transoms Most hardwood timber is now supplied in a green or ‘wet’ condition. Transoms should be ordered and delivered well in advance of their installation into the track to enable seasoning to occur. Transoms shall be cured for 12 months prior to installation.

The transoms should be ordered from the supplier 10mm oversize, to allow for shrinkage during the drying out process.

They should be delivered to a suitable compound, stored and rotated at regular intervals to control bowing.

C4-5.4 Transom acceptance requirements Check the quality of new transoms.

Are they marked as suitable for where you are going to install them?

The following acceptance requirements are extracted from RailCorp Specification SPC 311

The dimensional tolerances shall be in accordance with Table 2:

Dimension Acceptance Tolerance (mm)

Length + 50 - 0

Width + 25 - 0

Depth + 10 - 0

Table 2

All approved timbers shall be marked on one end in accordance with Table 3:

Cross Section (mm) Mark 250 x 150 Length Only 250 x 170 Vertical stripe - length 250 x 180 B – length 250 x 200 D – length

Table 3 Group 1 timbers are marked in white paint.

Group 2 timbers are marked in red paint.

All timber transoms shall be inspected and passed by a State Forests Timber Inspector prior to delivery for use on RailCorp tracks. Transoms shall not be coated before inspection.



All approved transoms shall be branded with a mark identifying the Inspector. The brand is to be clearly legible and located on the top face approximately 150mm from one end, and/or on the end grain section.

Are they in good condition?

Are the new transoms bored with the correct boring pattern for the location and the sleeper plates being used? See TMC 231 for details of boring patterns.

C4-5.5 Dressing and preparation of transoms C4-5.5.1 General

1 to 2 months prior to their installation, the timber transoms should be prepared and dressed including:

− Individual machining as determined by the survey, unless transom packers are proposed to be used

− Drilling of transom bolt holes in their correct locations as determined by the survey

− Chamfering of the ends to reduce splitting

− Application of an anti-slip paint with a white oil base to the ends of the transoms.

C4-5.5.2 Dressing Where individually sized, each transom should be numbered in their correct order from No.1 abutment through to No.2 abutment.

When machining a transom, any localised reduction in thickness of a transom must be achieved by a maximum 1 in 8 bevelling and rounded change of direction away from the reduced section (see Figure 1 below). Square cut notching is not permitted as it induces very high levels of concentrated stresses in the timber.

Figure 1

In the past, transoms were commonly square notched over the top flanges of the support girders in order to provide even seating, to account for super-elevation or as an additional back up lateral restraint to the transom bolt. These installations are to be rectified where necessary in the course of normal transom replacement programmes.

C4-5.5.3 Painting of transom ends All exposed transom surfaces within 200 millimetres of each transom end shall be painted a single coat with an approved white, oil-based enamel paint. The paint is to provide an anti-slip finish.

To achieve the anti-slip finish, either:

Max 1 in 8 slope

Rounded at junction TRANSOM



− Use an anti-slip paint suitable for external use on timber, such as a boat deck paint from marine suppliers; or

− Add grit particles to the existing paint being used. Grit particles are available from hardware stores.

C4-6 Transom fastening systems C4-6.1 Typical transom assemblies

Transom fastening assemblies include bolts, washers, nuts, pads, strips and packers. Typical assemblies are shown in Appendix 1.

Examples of typical approved transom assemblies are shown in Appendix 1, Figures 4 to 7. The assemblies include the transoms, holding down bolts, packer plates, resilient pads and zinc or polyester/PVC strips.

Figures 4 to 7 show the arrangement of components for various situations. The figures have been detailed using bolts with added nylon nuts but details are similar using other fastening systems.

Resilient fabric reinforced rubber pads/packers, zinc and polyester/PVC and some washers are common to all fastener systems.

Springs and associated washers are as described in this section. Conical springs, which are spiral when fully compressed, are used to maintain tension after transom shrinkage.

In girders fabricated from RSJs the underside of the top flange is angled. In order to maintain a satisfactory connection, a bevelled washer shall be installed between the head of the transom bolt and the flange. Since the angle varies in different RSJs matching bevelled washers need to be specified and installed.

On some bridges, large track plates cover the area of the transom bolts and it is necessary to recess the bolt heads into the top surface of the timber (see Figure 7). In this instance, the recesses should be cut during the dressing of the transoms.

Many transoms are attached to girders/stringers by a bolt on the outside of one girder flange and on the inside of the other. The bolt on the inside flange is to be relocated where practical to the outer flange when the transoms are due for replacement.

This policy is to be reviewed by the Civil Maintenance Engineer for bridges with narrow top flanges. In such instances, the advice of the Chief Engineer Civil should be sought as to whether the drilling of additional holes in the flange would reduce the compressive strength of the flange to a critical level.

C4-6.2 Transom bolts Transom bolts for securing the transoms to the girders are to be at least 22mm diameter.


For new bridges, bolts should be a minimum size of M24 and grade 8.8. The preferred bolt size is M30 where the axle load is 30 tonnes and either the track is curved or axle spacing is less than 1300mm.

For retransomming of existing bridges, bolt size shall be determined by compliance with edge distance requirements. Bolts should be a minimum size of M22 and grade 8.8.

Bolts are to be manufactured to meet the requirements of Australian Standard AS/NZS 1111.

The bolts may be:

− high strength hot-dip galvanised, or

− swage collar type, tension reduced to suit timber application.



If transoms shrink substantially, swage bolts become ineffective and shall be replaced.

If excessive transom shrinkage occurs, re-tensioning of the standard and nylon lock nuts is sufficient

C4-6.3 Nuts and washers Hexagon nuts for transom bolts shall be high strength hot-dip galvanised class 8.

Nylon lock nuts shall be plastic.

Washers shall be high strength hot-dip galvanised.

C4-6.4 Tensioning of transom bolts Bolts shall be installed to the snug-tight condition.

Snug-tight is the tightness attained by a few impacts of an impact wrench or by the full effort of a person using a standard podger spanner.

Nylon nuts are not to be over-tightened. Hand tight is sufficient.

C4-6.5 Transom packers Transom packers shall be used on all transoms.

Packers are used to ensure the load is centred on the girder.

Transom packers shall also be used to provide superelevation on bridges in preference to notching of transoms.

Transom packers may be galvanised steel plates or resilient rubber pads.

Resilient rubber pads shall only be used as transom packers on straight track as there may be lateral stability issues due to the shear stress of the rubber which will transfer extra lateral load to the transom bolt.

Steel packers shall be used where the track is on a curve or a transition. Steel packers shall also be used where the girder flange width exceeds 300 mm.

Transom packers are to be minimum 12 mm thick.

C4-6.5.1 Steel packer plates Galvanised steel packer plates shall measure 200mm x 250mm. The standard plate thickness is 12mm but various sizes may be utilized to achieve a smooth rail level.

A 5 mm thick resilient rubber pad is to be inserted under each steel packer to reduce dynamic load and slightly reduce noise.

The general details of steel packer plates are shown in Fig. 2 below:



Figure 2 - Transom Packer – Steel plate

Care needs to be exercised in specifying packer plates on girders with rivetted top flanges. Holes should be drilled into the packer plates to suit the rivet heads.

Packer plates and pads are to be installed generally as shown in Appendix 1. When positioning the packers, all effort should be made to centre the load over the girder web.

C4-6.5.2 Resilient pads Resilient, fabric reinforced, heavy type, rubber pads may be used as transom packers or as transom pads.

The surface hardness of the rubber pad shall be 80 Shore A durometer, ±10 durometer average with a minimum ultimate compressive strength of 48MPa.

The Fabreeka SA-47 elastomer bearing pad is an example of resilient pads approved for use.

Resilient rubber pad transom packers shall measure 200mm x 250mm. The standard thickness of the pads shall be 12 mm but various sizes may be utilized to achieve a smooth rail level. The maximum thickness shall be 20 mm.

The general details of resilient pad packers are shown in Figure 3:

Figure 3 Transom Packer – Resilient pad

As transom pads, the width and length of the pads shall match the width of both the transom and the girder flange. The thickness shall be 5 mm.

Where used they are to be installed as shown in Appendix 1.

26mm dia hole for transom bolt

30

Pad thickness to be increased as required

200mm x 250mm x 12mm

2/12mm dia rods to be plug welded and to project 6mm above plate. End to be rounded

26mm dia hole for transom bolt

30 50

50

Stamp thickness on this face (to be legible after galvanising)

200mm x 250mm x 12mm

Plate thickness to be increased as required



Where resilient pads are used without packer plates, they are to be nailed into the transom using heavy duty galvanised nails. Where a packer plate is used, the resilient pad should be glued to the packer plate.

C4-6.6 Zinc and polyester/PVC strips Zinc or polyester/PVC strips are to be installed on the top of the girder flanges, as shown in Appendix 1.

Zinc strips are to be 99.5% pure zinc and nominal 0.7mm thick.

Polyester/PVC compounded strips are to be UV stable, oil resistant, elastic and durable. The Wolfin GWSK membrane is an example of an approved product.

Where individual strips are used under the transoms only (i.e. not over the full length of the girder flange), they should be turned up at the ends and nailed to the side of the timber, to prevent movement and working loose.

C4-6.7 Prohibited configuration Some bridges with older transoms may still have an older fastening system based on the use of galvanised bolts fitted with a round washer and square washer under the head, together with a normal flat spring washer at nut. The nuts are secured by applying a tack weld to the bolt shank just above the nut.

This type of system is no longer an approved configuration and should be replaced when the transoms become due for renewal.



Chapter 5 Installation C5-1 General

This chapter describes the methods used in RailCorp to install or remove transoms using manual methods and minor plant and equipment.

There are two manual methods used to renew transoms, installation on a face and installation of individual transoms. The procedure for both these methods is described below.

C5-2 Site storage of materials On delivery of the transoms to site, they should be assembled in their correct order of numbering and orientation, ready for installation.

C5-3 Removal of existing transoms Following removal of the rails, the existing transom bolts are released and the old transoms lifted off the bridge.

Where possible, the transom bolts are to be removed with a spanner.

When transom bolts need to be removed by oxy cutting, the burning off is to occur only at the top surface of the transom and the bolt driven out through the transom.

Burning off of transom bolts adjacent to the top flange surface is not permitted, as burning damage cannot be tolerated on any

structural members of a railway bridge.

Transom bolts with conical springs must not be removed by oxy cutting or nut splitting methods unless staff are properly trained

and equipped. This precaution is due to the risk of explosive separation of the head from the body of the bolt because of the

energy stored in the spring.

Depending on the type of existing track plates, suitability for re-use and possession time, the existing track plates and fastenings may be removed for re-use on the new transoms or future use on another site.

C5-4 Transfer of transom bolts to outer flange The following procedures are to be observed when transferring the transom bolts from the inner flange to the outer flange:

− Holes are to be drilled only

− Holes are to be free of rag and perpendicular to the top flange

− Drilling is to be carried out by competent persons.

Burning is not permitted

Lateral positioning of holes:

− To be not less than 40 mm from edge to centre of hole

− To be at a sufficient distance from the web so that the head of the bolt clears the fillet of the girder

− The preferred distance from centre line of girder is 60mm (if bolts are kept as close as convenient to the web, less damage is caused by transom flexing under load).



Longitudinal positioning of holes:

− At abutments, the first holes are to be as near as practical to the girder ends but with the transom wholly supported by the girder flanges

− Holes are to be positioned as close as practical to the transom centrelines

− Holes are to be spaced as uniformly as practical along the span

− Ensure that no hole is located such that the bolt head will foul the edge of a stiffener or other attachment

− No hole is to be located within 50 mm of any other hole.

Hole sizes:

− 24 mm or 15/16 inch are suitable for 22 mm or 7/8 inch bolts - preferred option

− 26 mm or 1 inch are suitable for 24 mm bolts

− 25 mm are suitable where 22 mm bolts used but it is intended to upgrade to 24 mm bolts

− 32mm are suitable for 30mm bolts

− If existing (undersize) holes are to be used they must be enlarged by drilling or reaming only.

C5-5 Preparation of girder flanges Following removal of the old transoms and any old zinc strips, the top surfaces of the girder flanges under the transom seatings should be checked for corrosion. If necessary, the flanges should be cleaned back with a wire brush and painted with a rapid drying zinc-rich primer, prior to installing the new transoms.

C5-6 Installation of new transoms on a face 1. Cut the main running rails clear of the bridge ends

2. Remove fastening/anchors

3. Lift the rails out of the way

4. Unfasten guardrails on the bridge

5. Lift guardrails clear of the bridge

6. Remove track plates

7. Release transom bolts (see C5-3)

8. Remove the transom

− Remove the transom with sleeper tongs

− Place it clear of the track and stack transoms for disposal

9. Remove old packer plates, resilient pads and zinc strips

10. Prepare girder flanges (see C5-5)

11. Where transom bolts are to be transferred to outer flange, drill new holes for transom bolts (see C5-4)

12. Enlarge existing bolt holes, if required

13. Install zinc or polyester strips, resilient pads and packer plates in their correct sequence and position

14. Install new transoms in their correct sequence and position



− Install transoms with the heart of the timber down. The heart of the timber is the portion of the log that is near the growth centre (pith or log centre) and which is of reduced strength.

15. Install transom bolts, washers (bevelled washers on RSJ’s), conical springs and nuts

16. Tighten transom bolts

17. Where bolt holes have been recessed, fill the gap around the recessed bolt head with a suitable waterproof mastic caulking compound

18. Establish the correct track centreline in accordance with the survey and track design

19. Bore holes in transoms for track plates (if required)

20. Install track plates

21. Replace running rails

22. Check gauge (see Acceptance limits in TMC 231 Section C4-2 Item 12)

23. Reinstall track fastenings (see fastening requirements in TMC 231 Section C4-2 Item 14)

− If dogscrews and lockscrews are being used, follow the installation instructions in TMC 231 Chapter 10

− If transoms are being replaced at insulated joints and resilient fastenings are being used, make sure that low profile clips are used (See TMC 231 Chapter 7)

− If resilient fastenings are being used, make sure that zero toe load clips are used where required (See TMC 231 Chapter 8)

− DO NOT overdrive elastic fastenings (clips) Refer to TMC 231 Chapter 6 for installation instructions.

− Renew any ‘sprung” or overdriven clips

24. Reinstall anchors in non resilient fastened track (see anchoring requirements in TMC 231 Section C4-2 Item 15)

− Install anchors flush against the side of the transoms

− If the existing anchor pattern is more extensive than the requirements above, check with the Civil Maintenance Engineer to determine if the extra anchors need to be re-installed

− Renew any ‘sprung” or overdriven clips and anchors

25. Measure and record geometry

Heart down



26. Replace guard rails

27. Reinstall guard rail fastenings

28. Restore ballast profile where required on bridge ends (see acceptance limits in TMC 231 Section C4-2 Item 18)

29. Adjust and weld running rails (see TMC 221 – Rail Installation and Repair, TMC 222 – Rail Welding and TMC 223 – Rail Adjustment)

30. Check worksite

− Do not block drainage systems with old transoms, fastenings, plates, pads or strips

− Stack all used materials neatly where it is not in the way

31. Certify structure

− Certify the structure using the procedure in TMC 305 - Structures Assessment

32. Certify track

− Certify the track using the procedure in TMC 211

− If work has not been completed and transoms are left untied assess, whether a speed restriction is required using the operating limits in TMC 203

− If transoms have not been packed, or geometry has not been corrected apply appropriate restrictions in accordance with the operating limits in TMC 203.

C5-7 Installation of individual transoms C5-7.1 General

From time to time, it may be necessary to replace individual transoms on a bridge, e.g. following a fire or derailment, or to tie the track prior to face renewals. In this instance, the replacement transoms will need to be prepared and dressed by hand to suit the existing rail level and alignment.

Under these circumstances, the rails will not be removed but it may be necessary to release the fastenings on adjoining transoms to enable the rail to be jacked up sufficiently clear to remove the old transom and to install the new transom. The same procedures as above must be observed for removing the old transom bolts and preparing the girder flanges.

C5-7.2 Installation method 1. Remove rail and guard rail fastenings and anchors on the transom to be replaced and on sufficient adjacent transoms to allow rails and guard rails to be jacked clear to remove old transom and install new transom

Place track fastenings and anchors clear of the track and stack them so that they are ready for re-use or removal from site. Leaving them on the bridge will interfere with the retransomming process and may result in them falling off the bridge.

2. Remove transom bolts (see Section C5-3)

3. Install jacks under the rail

4. Jack up the rail

− BE extremely careful when lifting the track with jacks

− DON’T lift the track higher than is absolutely necessary



− DON’T lift the track between 1st November and 31st March, unless written instructions are issued to do so by the Civil Maintenance Engineer. (See TMC 211)

− DON’T lower the jacks without warning other staff

− DON’T leave jacks in place and unattended

5. Remove track plates

Place sleeper plates clear of the track and stack them so that they are ready for re-use or removal from site. Leaving them on the bridge will interfere with the retransomming process and may result in them falling off the bridge.

Check track plates to determine if they can be re-used by following the procedures in TMC 231 Chapter 11. Stack re-usable and scrap track plates separately and secure scrap plates so that they will not be re-used by mistake.

6. Remove transom/s

You may be able to remove more than one transom with one lift.

− Remove the transom with sleeper tongs

− Place it clear of the track and stack transoms for disposal

During removal DO NOT disturb the track geometry

7. Remove old packer plates, resilient pads and zinc strips

8. Prepare girder flanges (see C5-5)

9. Where transom bolts are to be transferred to outer flange, drill new holes for transom bolts (see C5-4)

10. Enlarge existing bolt holes, if required

11. Install zinc or polyester strips, resilient pads and packer plates in their correct sequence and position

12. Install new transom

− Lay the transoms, heart centre down

− Push the new transom into place

− Minimise disturbance to rail geometry

13. Install transom bolts, washers (bevelled washers on RSJ’s), conical springs and nuts

14. Tighten transom bolts

15. Where bolt holes have been recessed, fill the gap around the recessed bolt head with a suitable waterproof mastic caulking compound

16. Bore holes in transoms for track plates (if required)

17. Replace track plates

− Apply plates so that the rail leans towards the track centre

− Position the plate so that all holes in transom are visible through the holes in the plate

18. Lower the rails and remove the jacks



19. Check Gauge

20. Reinstall fastenings to rail and guard rail (see fastening requirements in TMC 231 Section C4-2 Item 14)

− If dogscrews and lockscrews are being used, follow the installation instructions in TMC 231 Chapter 10

− If transoms are being replaced at insulated joints and resilient fastenings are being used, make sure that low profile clips are used (See TMC 231 Chapter 7)

− If resilient fastenings are being used, make sure that zero toe load clips are used where required (See TMC 231 Chapter 8)

− DO NOT overdrive elastic fastenings (clips) Refer to TMC 231 Chapter 6 for installation instructions.

− Renew any ‘sprung” or overdriven clips

21. Reinstall anchors in non resilient fastened track (see anchoring requirements in TMC 231 Section C4-2 Item 15)

− Install anchors flush against the side of the transoms

− If the existing anchor pattern is more extensive than the requirements above, check with the Civil Maintenance Engineer to determine if the extra anchors need to be re-installed

− Renew any ‘sprung” or overdriven clips and anchors

22. Measure and record geometry

23. Reinstall guard rail fastenings

24. Restore ballast profile where required on bridge ends (see acceptance limits in TMC 231 Section C4-2 Item 18)

25. Check the worksite

− Do not block drainage systems with old sleepers, fastenings or plates

− Stack all used material neatly where it is not in the way

26. Certify structure

− Certify the structure using the procedure in TMC 305 - Structures Assessment

27. Certify track

− Certify the track using the procedure in TMC 211

− If work has not been completed and sleepers are left untied, assess whether a speed restriction is required using the operating limits in TMC 203

− If sleepers have not been packed, or geometry has not been corrected, apply appropriate restrictions in accordance with the operating limits in TMC 203.

C5-8 Cleaning up On completion of the work, the site is to be cleaned up and all released materials removed and disposed of in accordance with approved environmental practices.



Appendix 1 Typical Transom Assemblies



Typical assemblies using standard galvanized holding-down bolts are shown in Figures 4 to 7.

Galvanised Nut

Galvanised Washer Conical Spring (fully compressed)

Galvanised Washer (large)

Nylon nut turned loosely down onto galvanised nut

Girder Stringer or Deck girder

Transom bolt

Galvanised Washer

Continuous Zinc or polyester strip

Transom

Resilient Pad

Transom Packer (if required) (glued to Resilient Pad)

Galvanised Nut

Galvanised Washer

Conical Spring (fully compressed)Galvanised Washer (large)



Transom bolt

Galvanised Washer


Transom

Note: In some special applications where torsional load on girder is to be minimised leave spring 5mm uncompressed

Resilient Pad


Figure 4 - Assembly before tensioning bolt

Figure 5 - Assembly after tensioning bolt

RailCorp EngineTransoms

ering Manual — Structures TMC 311

© Rail Corporation of 25

Issued July 2010 1.1

Figure 4: - Assembly on Curved Track before tensioning bolt


Galvanised Washer

Galvanised Nut

Transom

UNCONTROLLED WHEN PRINTED Version

Conical Spring Galvanised Washer (large)


Transom bolt

Galvanised Washer


Resilient Pad


Note: May use insulated washer for this situation


Transom bolt (Counter bored)

Galvanised Washer

Transom

Galvanised Nut

Galvanised Washer

Conical Spring Galvanised Washer (large)



Note: Minimises Counterboring


Resilient Pad


Figure 7 - Assembly used with track fastening systems with large track plates

Figure 6 - Assembly used where large washer is too close to track plate

tmc 311 transoms - transport for nsw · engineer civil or chief engineer track as appropriate. c4-2...

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