aar track research program update€¦ · vertical split head inspection. low frequency eddy...

<Directory Number> - 1 © Transportation Technology Center, Inc., a subsidiary of the Association of American Railroads, 2003

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AAR Track Research Program UpdateAAR Track Research Program Update

Report to AREMA Annual Conference Report to AREMA Annual Conference Track SectionTrack Section

October 7, 2003October 7, 2003

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<Directory Number> - 2 © TTCI/AAR, 2003

Problem definition:Problem definition:Increased tonnage and HAL will cause increased Increased tonnage and HAL will cause increased wear and tear on track structureswear and tear on track structures

Track caused accident rate has increased since Track caused accident rate has increased since 19951995Substantial train delay due to maintenance & repair Substantial train delay due to maintenance & repair of special track work, bridge components, broken of special track work, bridge components, broken rails and welds rails and welds Rail base defects, rail weld defects and certain Rail base defects, rail weld defects and certain transverse rail defects masked by shells are difficult transverse rail defects masked by shells are difficult to detect.to detect.Turnouts and crossing diamonds are the most costly Turnouts and crossing diamonds are the most costly and maintenance intensive elements of track and maintenance intensive elements of track structure. Insulated joints have become a significant structure. Insulated joints have become a significant problem.

Engineering Research ProgramEngineering Research Program

problem.

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Engineering Research ProgramEngineering Research ProgramProblem definition:Problem definition:

Increased tonnage and HAL will cause increased Increased tonnage and HAL will cause increased wear and tear on track structures (Continued)wear and tear on track structures (Continued)

Bridges are the largest track asset. They have been Bridges are the largest track asset. They have been identified as potential economic barriers to axle identified as potential economic barriers to axle loads above 286Kloads above 286K

Despite major improvements in rail performance, Despite major improvements in rail performance, RCF resistant steels are needed for heavy haul RCF resistant steels are needed for heavy haul operationsoperations

Field welds account for 1/3 of all rail defects on Field welds account for 1/3 of all rail defects on some some RRsRRs

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AAR Engineering Research ProgramAAR Engineering Research Program

Track Integrity MonitoringTrack Integrity Monitoring

Special Track WorkSpecial Track Work

Bridge ResearchBridge Research

Track ComponentsTrack Components

Heavy Axle Loads/ FASTHeavy Axle Loads/ FAST

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Track Integrity Track Integrity –– Improved Rail Flaw DetectionImproved Rail Flaw Detection

Objectives:Objectives:Improve reliability and accuracy of Improve reliability and accuracy of rail defect detection systemsrail defect detection systems

Major Tasks in 2003:Major Tasks in 2003:Detector car evaluations at RDTFDetector car evaluations at RDTF

Facilitate development of advanced Facilitate development of advanced NDT technologyNDT technology

LaserLaser--Air Hybrid Ultrasonic Testing Air Hybrid Ultrasonic Testing (LAHUT)(Johns Hopkins University)(LAHUT)(Johns Hopkins University)Low Frequency Eddy Current Low Frequency Eddy Current (LFEC)(LFEC)

Cooperative efforts with FRACooperative efforts with FRARail defect growth evaluationRail defect growth evaluationService failure characterizationService failure characterization

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Track Integrity Track Integrity –– Improved Rail Flaw DetectionImproved Rail Flaw Detection

Key findings:Key findings:The growth of various flaws are being The growth of various flaws are being monitored “in track,” at FAST monitored “in track,” at FAST

Monitoring provides “real” flaw Monitoring provides “real” flaw growth datagrowth dataValidation of fracture mechanics Validation of fracture mechanics based models based models Defect management tool to optimize Defect management tool to optimize rail inspection strategiesrail inspection strategies

Initial Pulse

A-scan

Flaw

Reflected Signal

Transmitted Signal

Service failure characterizationService failure characterizationFlaw orientation influences detection Flaw orientation influences detection capability. Ex: 44% CHA defectcapability. Ex: 44% CHA defect

Flaw orientation at 90 degrees Flaw orientation at 90 degrees from perpendicularfrom perpendicular

Shelling reflects ultrasonic signal Shelling reflects ultrasonic signal masking transverse defects (masking transverse defects (TDsTDs))

5% Detail Fracture

25% Detail

Fracture

slower growth

45% Detail

Fracture

faster growth

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Laser

Capacitive Capacitive AirAir--Coupled Coupled TransducerTransducer

VSH

Rail

130 140 150 160 170 180 190 200 210 220 230-30

-20

-10

0

10

20

30

Sig

nal A

mpl

itude

Time (µs)

SC1.114

130 140 150 160 170 180 190 200 210 220 230-40

-30

-20

-10

0

10

20

30

40

Sig

nal A

mpl

itude

Time (µs)

SC1.111No Crack

Crack

LAHUT Proof of Concept LAHUT Proof of Concept Vertical Split Head InspectionVertical Split Head Inspection Low Frequency Eddy Low Frequency Eddy

CurrentCurrentTargets Targets TD’sTD’s and and TD’sTD’s under shellsunder shells

Ultrasonic TestingUltrasonic TestingTargets head, web, Targets head, web, and base defects and base defects usingusing

Phased array Phased array technologytechnologyLaser Laser technologytechnology

Emerging Technologies for Rail Defect DetectionEmerging Technologies for Rail Defect Detection

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Track Integrity Track Integrity –– Improved Rail Flaw DetectionImproved Rail Flaw DetectionPath ForwardPath Forward

The LAHUT system is conceptually sound The LAHUT system is conceptually sound Make technology available to the railroad industry Make technology available to the railroad industry

System requires further development such as:System requires further development such as:Optimize transducer setup for various defect typesOptimize transducer setup for various defect typesField design for laser and opticsField design for laser and opticsAutomated pattern recognition systemAutomated pattern recognition system

Laser to Air Coupled Ultrasonic InspectionLaser to Air Coupled Ultrasonic InspectionRemote/nonRemote/non--contact NDT method with contact NDT method with

demonstrated base inspection capabilitydemonstrated base inspection capability

Laser beam Air-coupled transducer

Laser beam Air-coupled transducer

rail base

rail base

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Improved Rail Flaw Detection Improved Rail Flaw Detection -- SummarySummary

North American detector car evaluations North American detector car evaluations show reliability in line with AREMA show reliability in line with AREMA guidelines for detail fractures between guidelines for detail fractures between the sizes of 10 to 30 percent CSHAthe sizes of 10 to 30 percent CSHACharacterization of service failures (i.e., Characterization of service failures (i.e., missed flaws) assists in increasing missed flaws) assists in increasing detection reliability by providing a greater detection reliability by providing a greater understanding of the inspection understanding of the inspection environmentenvironment

Development of LAHUT and LFEC NDT Development of LAHUT and LFEC NDT systems are continuing to be pursued to systems are continuing to be pursued to increase the reliability of inspection for the increase the reliability of inspection for the total rail section (head, web, and base)total rail section (head, web, and base)

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SRI 9: Special Track WorkSRI 9: Special Track Work

Major Tasks in 2003Major Tasks in 2003Evaluation of existing insulated joint designsEvaluation of existing insulated joint designsTesting of new design turnout prototype at FASTTesting of new design turnout prototype at FASTAAR Switch Point EvaluationAAR Switch Point EvaluationRevenue Service Evaluation of Frog Running Surface Revenue Service Evaluation of Frog Running Surface Profile DesignsProfile DesignsBainitic Steel Frog Revenue Service TestsBainitic Steel Frog Revenue Service TestsRamped Crossing Revenue Service EvaluationRamped Crossing Revenue Service EvaluationFlange Bearing Frog Revenue Service EvaluationsFlange Bearing Frog Revenue Service EvaluationsReduced Impact Foundation DesignReduced Impact Foundation DesignBridge Joint Performance AnalysisBridge Joint Performance AnalysisSpecial Track Work Component EvaluationsSpecial Track Work Component EvaluationsReports & Reports & TD’sTD’s: 7 issued in 2002, 4 in 2003: 7 issued in 2002, 4 in 2003

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Insulated Joint Failure ModesInsulated Joint Failure Modes(from examination of HAL joints)(from examination of HAL joints)

0%10%20%30%40%50%60%70%80%90%

100%

Resist

ance

Debon

ding

Thimble

sBar In

sul.

End Pos

tBrok

en B

olts

Bolt Hole

Crac

kLo

ose B

olts

Bar Crac

k

DEFECTS

OC

CU

REN

CE

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Analysis of Failed JointsAnalysis of Failed Joints

Thimble –Cracked with Rust

Bar Insulation –Worn and Rubbing

with Rail

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Special Track Work Research Special Track Work Research Damped Crossing Foundation DesignDamped Crossing Foundation Design

Background: Background: The special loading conditions of frogs (i.e. The special loading conditions of frogs (i.e. high impacts) cause track degradation. high impacts) cause track degradation. TTCI analysis suggests that adding TTCI analysis suggests that adding damping to the crossing will lower damping to the crossing will lower maximum dynamic loadsmaximum dynamic loads

Modeling suggests optimal properties to Modeling suggests optimal properties to lower dynamic loads (~300 lb/in/sec/tie)lower dynamic loads (~300 lb/in/sec/tie)Hammer tests show that track damping Hammer tests show that track damping is below optimal (~50 lb/in/sec/tie)is below optimal (~50 lb/in/sec/tie)

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Predicted Optimal DampingPredicted Optimal Damping

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Comparison of Measured Track Damping Comparison of Measured Track Damping with Optimal Dampingwith Optimal Damping

OptimalOptimal

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FAST Damping Test PanelFAST Damping Test Panel

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Frog Running Surface Profile DesignFrog Running Surface Profile Design

Longitudinal & Cross section profile frogsLongitudinal & Cross section profile frogsDesigned to reduce impacts from nonDesigned to reduce impacts from non--conformal conformal wheel profileswheel profilesDesigned to reduce contact stresses, metal flow Designed to reduce contact stresses, metal flow grindinggrinding

Revenue Service & FAST results after 150 Revenue Service & FAST results after 150 -- 200 200 MGT:MGT:—— Reduced maintenanceReduced maintenance—— Wider wheel/rail contact bandWider wheel/rail contact band—— 1 weld repair at 110 MGT1 weld repair at 110 MGT—— Reduced point deformationReduced point deformation—— Wings showing RCF & flowWings showing RCF & flow

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Frog Running Surface ProfilesFrog Running Surface ProfilesProfile frogs in Revenue ServiceProfile frogs in Revenue Service

UP Laramie, WYUP Laramie, WYMixed FreightMixed Freight

BNSF BNSF BragdonBragdon, CO, COUnit coal, Mixed FreightUnit coal, Mixed Freight

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SRI 9: Special Track WorkSRI 9: Special Track WorkSummarySummary

Ready to ImplementReady to ImplementFBF diamondsFBF diamondsFrog running surface profilesFrog running surface profilesBainitic steel for high angle diamondsBainitic steel for high angle diamonds

Under DevelopmentUnder DevelopmentNext generation TO for FASTNext generation TO for FASTDamped foundationsDamped foundationsGuard rail designsGuard rail designsBridge (Rail) jointsBridge (Rail) jointsTampableTampable switchswitchInsulated jointsInsulated joints

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SRI#10A Steel BridgesSRI#10A Steel BridgesObjective:Objective:

Develop guidelines to extend the life of existing Develop guidelines to extend the life of existing steel bridges, to better assess capacity, and to steel bridges, to better assess capacity, and to prioritize maintenance and replacementsprioritize maintenance and replacements

Deliverables:Deliverables:CWR Effects on Long Steel BridgesCWR Effects on Long Steel BridgesCapacity Assessment of Steel Bridges for HAL Capacity Assessment of Steel Bridges for HAL Lateral ForcesLateral ForcesHAL Effects on Welded Steel BridgesHAL Effects on Welded Steel Bridges

Ultrasonic Impact Treatment (UIT) TechniqueUltrasonic Impact Treatment (UIT) TechniqueAcoustic Emission Monitoring of Crack GrowthAcoustic Emission Monitoring of Crack Growth

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CWR Issues on Long BridgesCWR Issues on Long BridgesCWR broken rail force ~ 1000 kips long. force into bridgeCWR broken rail force ~ 1000 kips long. force into bridgeRail joints often used with CWR on long bridges to minimize Rail joints often used with CWR on long bridges to minimize rail forces into bridgerail forces into bridgeBridge rail joint at FAST increased rate of crack growthBridge rail joint at FAST increased rate of crack growthRail anchoring if no joints, to minimize buckling potentialRail anchoring if no joints, to minimize buckling potentialTradeoffs: Cost of joints, joint maintenance, and bridge impact Tradeoffs: Cost of joints, joint maintenance, and bridge impact damage vs. broken / buckled rails, bridge and deck damagedamage vs. broken / buckled rails, bridge and deck damage

Crack Growth Rate Comparison

0

0.005

0.01

0.015

0.02

0.025

0.03

Cra

ck G

row

th R

ate

(Inch

es/M

GT)

Before Joint Joint Installed After Joint

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Steel Bridge Lateral ForcesSteel Bridge Lateral ForcesCurrent design guidelines date to 1936, HAL equipment ~1986.Current design guidelines date to 1936, HAL equipment ~1986.

No existing rating guidelinesNo existing rating guidelinesHAL rev. svc. loads similar to AREMAHAL rev. svc. loads similar to AREMACapacity assessment HAL lateral forces Capacity assessment HAL lateral forces

Stronger new designsStronger new designsAppropriate rating guidelines Appropriate rating guidelines to prioritize bridge maintenanceto prioritize bridge maintenance

Western US Coal LineLead Axle Net Lateral Force

Distribution: Normal

-4 -3 -2 -1 0 1 2 3 4

Theoretical Quantile

0.01 0.05 0.25 0.50 0.75 0.90 0.99

-2

0

2

4

6

8

10

12

14

16

18

20

22

Forc

e (k

ips)

AREMA Design

Typical Rating Level

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Right Side Weld Crack 5/23/01 - 6/21/01

slope = 8.5 counts/cycle

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1000000

0 20000 40000 60000 80000 100000 120000 140000

Bridge Span Displacement Cycles*Crack Growth is not Linear

AE

Cou

nts

0

0.05

0.1

0.15

0.2

0.25

0.3470 472 474 476 478 480 482 484 486 488 490

Million Gross TonsC

rack

Gro

wth

(Inc

h)*

Ultrasonic Impact Treatment of Ultrasonic Impact Treatment of Welds in GirdersWelds in Girders

Can UIT prevent cracking at Can UIT prevent cracking at welds?welds?Initial application showed 7 Initial application showed 7 ksiksireduction in residual stress reduction in residual stress (nominal live load stress : 9ksi) (nominal live load stress : 9ksi) Long term monitoring ongoing Long term monitoring ongoing at FASTat FAST

Acoustic Emission Monitoring of Acoustic Emission Monitoring of Fatigue Crack GrowthFatigue Crack Growth

Long term monitoring at FAST has Long term monitoring at FAST has helped accumulate 700 MGT on bridge helped accumulate 700 MGT on bridge with major crack in tension flangewith major crack in tension flangeAE shows major crack is not growing AE shows major crack is not growing noticeablynoticeablyLack of growth confirmed with recent XLack of growth confirmed with recent X--ray and ultrasonic inspectionsray and ultrasonic inspectionsAE provides early warning for AE provides early warning for remedial actionremedial action

Welded Steel BridgesWelded Steel Bridges

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Steel Bridge SummarySteel Bridge Summary

HAL Lateral ForcesHAL Lateral ForcesFinal statistical analysis work in progressFinal statistical analysis work in progress

CWR IssuesCWR IssuesTest plan in progress for rev. svc. bridge testTest plan in progress for rev. svc. bridge testAwaiting new bridge joint for FAST testingAwaiting new bridge joint for FAST testing

Welded Bridge IssuesWelded Bridge IssuesMonitoring of UIT long term performance ongoingMonitoring of UIT long term performance ongoingAE testing continuing on FAST steel bridgeAE testing continuing on FAST steel bridgeLooking for good field demo site for AE installationLooking for good field demo site for AE installation

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SRI#10B Concrete BridgesSRI#10B Concrete BridgesObjective:Objective:

Maximize service life, reduce maintenance, and Maximize service life, reduce maintenance, and reduce HALreduce HAL--related problems with concrete related problems with concrete railroad bridgesrailroad bridges

Deliverables:Deliverables:Install concrete bridge at FASTInstall concrete bridge at FAST

Tie & ballast performance on concrete bridge Tie & ballast performance on concrete bridge decksdecks

Shear crack issues on concrete bridge spansShear crack issues on concrete bridge spans

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FAST Concrete Bridge PlansFAST Concrete Bridge Plans

3

373839

40

41

2

1

33

32

31 30

28 27 26

25

242398

7

6

5

4

36

29

35

High Tonnage Loop

Proposed ConcreteBridge Location

ExistingSteel Bridge Location

Conventional and State-of-the Art

Bridges

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Key DonationsKey Donations

UP to donate 2 stateUP to donate 2 state--ofof--thethe--art spansart spansCN to donate High Performance Concrete spanCN to donate High Performance Concrete spanRinkerRinker Materials to donate 2 conventional Materials to donate 2 conventional spansspansCP to design caps and foundationsCP to design caps and foundationsCSX and NS to donate pilesCSX and NS to donate pilesUP to drive pilesUP to drive pilesBNSF to assist with general constructionBNSF to assist with general constructionRinkerRinker Materials to donate caps and Materials to donate caps and backwallsbackwallsWaterproofing suppliers to apply waterproofingWaterproofing suppliers to apply waterproofing

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SRI#11A Advanced Rail SteelsSRI#11A Advanced Rail SteelsObjective:Objective:

Develop and/or demonstrate advanced rail steels Develop and/or demonstrate advanced rail steels giving lower lifegiving lower life--cycle costs than current rail steelscycle costs than current rail steels

Significance of Rail Research:Significance of Rail Research:The AAR/TTCI bainitic steel research program begun The AAR/TTCI bainitic steel research program begun in mid 1980s spurred advances in the field of rail in mid 1980s spurred advances in the field of rail metallurgymetallurgy

Three manufacturers currently investigating bainitic rail Three manufacturers currently investigating bainitic rail Rail Expenditures:Rail Expenditures:

$17.4 billion expenditures on rail and other track $17.4 billion expenditures on rail and other track materials in the last ten yearsmaterials in the last ten yearsRail breaks are the most common cause of trackRail breaks are the most common cause of track--related derailments totaling $142 million in track and related derailments totaling $142 million in track and equipment repairs over the last three yearsequipment repairs over the last three years

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Program Information and IssuesProgram Information and IssuesJ6 Bainitic RailJ6 Bainitic Rail

Exceptional rolling contact fatigue performanceExceptional rolling contact fatigue performanceMixed wear performanceMixed wear performanceSpecial track work performance exceptionalSpecial track work performance exceptionalWelding and 141AB section performance issuesWelding and 141AB section performance issues

Current Research CourseCurrent Research CoursePerform research to allow welding and manufacture of Perform research to allow welding and manufacture of 141AB J6 rail 141AB J6 rail

Alternative Course of ActionAlternative Course of ActionInvestigate ultra high carbon steel (UHCS) for use as Investigate ultra high carbon steel (UHCS) for use as rail with 1.3 to 2.1% carbon [rail with 1.3 to 2.1% carbon [ 430430--500 HB]500 HB]

This will accelerate current manufacturer trend to This will accelerate current manufacturer trend to higher carbonhigher carbon

Continue UIUC research to optimize rail metallurgyContinue UIUC research to optimize rail metallurgy

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SRI#11B Improved Rail WeldingSRI#11B Improved Rail WeldingObjective:Objective:

Develop and test improved techniques, materials, Develop and test improved techniques, materials, installation, and maintenance procedures to enhance installation, and maintenance procedures to enhance the reliability and utility of rail weldsthe reliability and utility of rail welds

Techniques:Techniques:Minimize the number of thermite welds in trackMinimize the number of thermite welds in trackAlternative rail welding methods with enhanced Alternative rail welding methods with enhanced performanceperformanceImprove the performance of current Improve the performance of current thermitethermite weldsweldsDevelopment of timely laboratory evaluation Development of timely laboratory evaluation technique for rail weldstechnique for rail welds

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Rail Welding Key FindingsRail Welding Key FindingsWideWide--Gap WeldsGap Welds

Laboratory test results consistent with1Laboratory test results consistent with1--inch weldinch weldFatigue performance superior to 1Fatigue performance superior to 1--inchinch

WGW usage implemented by UP and BNSFWGW usage implemented by UP and BNSFGasGas--Pressure WeldingPressure Welding

Laboratory results equal or superior to flashLaboratory results equal or superior to flash--butt butt InIn--track GPW equipment currently being developed track GPW equipment currently being developed in Japan and Chinain Japan and China

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Rail Welding Key FindingsRail Welding Key FindingsThermite Weld ImprovementsThermite Weld Improvements

UIUC thermite weld FEA research UIUC thermite weld FEA research –– preliminary resultspreliminary resultsVariability in thermite reaction (heat output) may be Variability in thermite reaction (heat output) may be controlling factorcontrolling factor

Utilization of WGW for compromised jointsUtilization of WGW for compromised joints11--inch comp joints no longer allowed in UKinch comp joints no longer allowed in UK

Fatigue testing of rail weldsFatigue testing of rail weldsBetter replicates service Better replicates service conditionsconditionsProvides timely dataProvides timely data

2 million cycles in 10 days2 million cycles in 10 daysLarge database accumulatedLarge database accumulated

050

100150200250300350400

10000 100000 1000000 10000000

cycles

Std TW Std EFW Rail GPW

CyclesLo

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aar track research program update€¦ · vertical split head inspection. low frequency eddy...

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