Research On Wear Tracking Experiment And Reprofiling For New Design Tread Of EMU

Wheels, as part of EMU’s moving components, will wear when running on the rail,which impacts directly on the wheel/rail geometry contact relationship and affects the vehiclevibration performance, influences ride comfort and safety. Railway maintenance departmentsimprove the wheel/rail geometry contact relationship, ride comfort and safety by applyingsome strategies for reprofiling wheel tread. Reprofilng cycle is a key link in reprofilingstrategy, which not only affects the ride comfort and safety, but also directly determines theservice life of wheels.CRH1EMU needs to be formulated reprofiling cycle urgently after applyingnewly-designed LMD tread. For this purpose, the wear tracking experiment lasted for morethan one year was carried out on a existing railway line. The reprofiling cycle was determinedin four dimensions, including wheel wear performance, vehicle vibration performance,analysis of using data and vehicle dynamics simulation. And EMU has been operated andassessed during a next repfofiling cycle. Conclusions are as follows:(1) Tread and flange’s wear loss increases with the increase of running mileage, tread’swear speed remains stable, and flange’s wear speed gradually decreases and tends to be stablewith the increase of running mileage during tracking and assessment period; there is aphenomenon that wheel flanges have partial wear minorly; Wheel/rail geometry contact statusis less inclined to be deterioration; Equivalent conicity increases firstly and then decreaseswith the increase of running mileage during tracking period, while equivalent conicityincreases slowly during assessment period; And equivalent conicity meet the prescribedstandards for each wheelset during different periods.(2) The carbody lateral stability that was steadily superior and lateral acceleration ofbogie frame that was higherly stable increases slowly with the increase of running mileage,while carody vertical stability that was steadily superior remains stable basicly during thetracking period. Vehicle lateral stability increases slightly, as well as, vertical stability andlateral acceleration changes finely, and all indexes do not appear obvious increasing and tendto be bad during assessment period.(3) It is a good situation for EMU operation that wheel diameter, flange thickness, flangeheight, qR value can satisfy the requirements of maintenance and wheel rolling diameterdifference is normal during tracking and assessment period.(4) Vehicle dynamics performance simulation verify that the vehicle critical speed andbogie stability can satisfy the requirements of vehicle operation, as well as, carbody lateraland vertical stability are excellent, worn tread is adaptive to the varying rail parameters, and performance of vehicles passing the curve is good.(5)300,000km is set as the reprofiling cycle for CRH1EMU based on the analysis offour aspects; It is suggested to select some EMUs of CRH1to carry out wear tracking test for350,000km reprofiling cycle due to lager difference between values of reprofiling cycleevaluation index and standard limit.