Wheel Profile Maintenance Guidelines (2015) / Chapter Skim
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Wheel Profile Maintenance Guidelines PART 3 Development of New Wheel Profiles for Port Authority Trans-Hudson
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TCRP WOD 65 Part3 Table of Contents TABLE OF CONTENTS ...............................................................................................................................
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TCRP WOD 65 Part3 List of Figures Figure 1. Measured Newly Trued and Worn Wheel Profiles ..........................................................
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TCRP WOD 65 Part3 Figure 24. Slightly Worn and Moderately Worn Rail Profiles Measured on Tangent Track .......
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TCRP WOD 65 Part3 Summary Transit Cooperative Research Program's project (TCRP D7 Task Order 20: wheel profile maintenance guidelines for transit systems) has an objective to demonstrate the application of guidelines and procedures developed in a selected transit system.
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TCRP WOD 65 Part3 C H A P T E R 1 Introduction Transportation Technology Center, Inc.
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TCRP WOD 65 Part3 C H A P T E R 2 Methodology The following methodology was used in the development of a new wheel profile: 1. Review of current wheel/rail interface issues 2.
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TCRP WOD 65 Part3 C H A P T E R 3 Review of Current Conditions PATH has been operating PA5 cars in revenue service since 2009. The PA5 cars are 51 feet (16 meters)
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TCRP WOD 65 Part3 Figure 2 shows rail profiles that were measured on tangent tracks and curves at PATH. High wear rates were observed not only on high rails, but also on restraining rails adjacent to the low rails due to the small curve radii.
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TCRP WOD 65 Part3 C H A P T E R 4 Generation of Candidate Profiles An optimized wheel profile should provide the following: • Stable performance over the range of normal train speeds • Safety from derailment under normal operating conditions • Maximized wheel and rail life by decreasing wear The following three general guidelines are used in wheel profile design: • The wheel flange angle should be at least 72 degrees, preferably 75 degrees, to protect against flange climbing derailments. • The slope of the wheel tread (tread taper)
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TCRP WOD 65 Part3 Figure 4. Existing and Proposed Wheel Template Profiles Figure 5.
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TCRP WOD 65 Part3 Figure 6. Contact between Worn Rail and Existing AAR S-622-78 Wheel Template Profiles Figure 7 shows that the proposed wheel profile closely matches the worn rail profile with little gap in the gage corner to allow the wheels to quickly wear conformal to the rails.
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TCRP WOD 65 Part3 C H A P T E R 5 Dynamic Performance Evaluation 5.1 Performance Criteria Profile design is a matter of optimizing several criteria. Some criteria must be satisfied; others can be compromised to achieve an overall optimum solution.
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TCRP WOD 65 Part3 3. Slightly worn rail measured on tangent track located at milepost 1092+10 in Tunnel A-4 4.
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TCRP WOD 65 Part3 Figure 8 shows that the proposed wheel profile produces the lowest wear indices among all simulated rail profiles. The APTA 240 wheel provides the second lowest wear indices.
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TCRP WOD 65 Part3 Figure 10. Rolling Resistances for Alternative Wheel and Rail Profiles – 147-foot Radius Curve Figure 11 shows that the APTA 240 wheel produces the lowest rolling resistance on all simulated new rail profiles on a 300-foot radius curve, and the proposed wheel produces the second lowest rolling resistance.
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TCRP WOD 65 Part3 5.3.3 Contact Stress Figure 12 compares the flange contact stress from the outside wheel of PA5 car on the high rail of a 147-foot radius curve for all combinations of wheel and rail profiles that have been modeled. Figure 12.
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TCRP WOD 65 Part3 5.3.4 Contact Angle The maximum contact angle on the outside wheel of the lead axle during flange contact is 75 degrees for the proposed wheel profile. The maximum contact angle of existing S-622-78 wheel profile is 72 degrees.
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TCRP WOD 65 Part3 Figure 15. L/V Ratios for Alternative Wheel and Rail Profiles – 300-foot Radius Curve A safe value of L/V ratio depends on the wheel/rail friction conditions and the distance over which the L/V ratio is high.
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TCRP WOD 65 Part3 Figure 16 shows the lowest hunting speed (50 mph) occurs with the APTA 240 wheel running on 100RB rails indicating an unsafe operating condition.
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TCRP WOD 65 Part3 Figure 17. RRD for Alternative Wheel Profiles on New 100RB Rails Figure 17 shows that the APTA 240 wheel profile produces a step increase in RRD with lateral shift before flange contact is made, which generates the highest conicity.
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TCRP WOD 65 Part3 Figure 18. Comparisons of Axle and Truck Movement between APTA 240 and S-622-78 Wheels Figure 19 shows the lowest hunting speed occurs with the APTA 240 wheel running on AREMA 115RE rails.
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TCRP WOD 65 Part3 Clearly, the increase of hunting speed was caused by the change of rail profiles, because other parameters used in the modeling did not change. Figure 20 overlays the two rail profiles.
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TCRP WOD 65 Part3 Figure 21. Rolling Radius Difference for Alternative Wheel Profiles on New 115RE Rails Figure 22.
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TCRP WOD 65 Part3 Figure 23. Truck Frame Lateral Acceleration for Alternative Wheel Profiles – Moderately Worn Rail Measured on Tangent Track Figure 24 compares the slightly worn and moderately worn rail profiles measured on tangent track.
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TCRP WOD 65 Part3 C H A P T E R 6 Validation The curving and hunting performances of the proposed new wheel profile were further evaluated through simulation using measured track geometry and rail profiles from PATH. The track geometries, as Figure 25 shows, were measured from Journal Square Station to Exchange Place Station.
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TCRP WOD 65 Part3 Figure 26 shows the time histories of the truck frame lateral acceleration, W/R forces, and wheel L/V ratios of the P5A car with three different alternative wheel profiles at a speed of 60 mph. On tangent track from 500 to 3,000 feet, the time history peak values were dominated by responses using APTA 240 wheels (red color)
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TCRP WOD 65 Part3 Figure 27. Comparisons of Truck Frame Lateral Acceleration RMS Values Figure 28 shows the wheel L/V ratio of the P5A car equipped with APTA 240 wheel is the lowest among three simulated wheels, indicting the best curving performance.
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TCRP WOD 65 Part3 Figure 28. Comparisons of Wheel L/V Ratios Clearly, the proposed new design wheel, which has similar hunting performance but better curving performance than the existing cylindrical wheel, demonstrates overall optimal dynamic performances under various track conditions.
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TCRP WOD 65 Part3 C H A P T E R 7 Conclusions and Recommendations Preliminary analysis has shown that the proposed new wheel profile provides the overall best performance among all wheel profiles that were considered. The wheel wear index, contact stress, rolling resistance, and L/V ratio of the proposed new wheel profile are lower than those of the existing cylindrical AAR S-622-78 wheel template profile.
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TCRP WOD 65 Part3 References American Public Transit Association. APTA SS-M-015-06, Standard for Wheel Flange Angle for Passenger Equipment, 2007.
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TCRP WOD 65 Part3 A P P E N D I X A Proposed New Wheel Profile Arc Radius, Arc Center, and Segment Point Coordinates Figure A-1. Proposed New Wheel Profiles Table A-1.
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TCRP WOD 65 Part3 A P P E N D I X B Proposed New Wheel Profile (X,Y) Coordinates Table B-1.
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