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FLANGE CLIMB DERAILMENT CRITERIA AND WHEEL/RAIL PROFILE MANAGEMENT AND MAINTENANCE GUIDELINES FOR TRANSIT OPERATIONS SUMMARY The objective of this research was to improve wheel/rail interaction in transit systems by introducing flange climb derailment criteria and wheel/rail profile management and maintenance guidelines that can be applied to transit operations. This work was started with a survey conducted on six representative transit systems to define the common problems and concerns related to wheel/rail profiles in transit operation. As an integral part of the survey, the research team provided wheel/rail inter- action training seminars to maintenance and engineering staff at each of the systems. The survey results are compiled in Appendix A of this report, and Appendices B and C discuss the development of flange climb derailment criteria for transit vehicles. The flange climb derailment criteria developed include a wheel lateral-to-vertical (L/V) ratio limit and a corresponding flange-climb-distance limit. These criteria were developed based on computer simulations of single wheelsets, and representative transit vehicles. The resulting criteria are shown to be dependent on wheel/rail contact angle, wheel/rail friction coefficient, flange length, and wheelset angle of attack (AOA). The wheel profiles used in the simulations were obtained from the transit system survey. These profiles were applied to simulations of both light rail and rapid transit vehicles with flange angles ranging from 60 degrees to 75 degrees and flange length ranging from 0.395 to 0.754 in. The proposed criteria were validated using flange-climb test data collected with the research team Track Loading Vehicle (TLV). An example of applying the criteria to a passenger car test is given in the report. The limitations of the proposed criteria are also discussed. A general form of flange-climb-distance criterion is proposed in this report. It applies to an L/V ratio equal to or less than 1.99. A biparameter regression technique was developed to derive the distance criterion, which is more accurate and less conserva- tive, but only for the specific wheel and rail simulated. Because of the wide diversity of practices currently applied, it is not possible to set universal rules that can be applied to all transit systems. However, it is beneficial to rec- ommend general guidelines that transit operations can follow in their wheel and rail maintenance practice. Therefore, some guidelines in this report are rather more concep- tive than quantitative. Guidelines and recommendations applying to the management

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2 and maintenance of wheel/rail profiles for transit operations involving the following areas have been provided: New wheel profile drawings Wheel/rail profile measurement and documentation Wheel/rail profile assessment Wheel re-profiling Wheel profile design Ground rail profile design Effect of gage and flange clearance on wheel/rail interaction Wheel/rail profile monitoring program