Wheel-Rail Profile Matching Relation Of Metro Vehicles

Subway is an efficient,convenient and fast transportation.Its operating speed is obviously lower than that of high-speed railway trains.The running lines are either underground or elevated,and the lines are fixed.These characteristics inevitably lead to the wheel-rail relationship of subway vehicles with certain particularity,especially wheel-rail wear,tread peeling,rim contact,etc.wheel-rail profile matching is one of the main ways to solve these problems,so it is necessary to carry out research on wheel-rail profile matching of subway vehicles.Through dynamic simulation calculation,this paper compares and analyzes the wheel-rail contact relationship and vehicle dynamic performance of the LM profile widely used in China,the European S1002 profile(considering the inner distance of the wheelset 1360 mm)and the LMB profile improved from the S1002 profile which is suitable for China’s railway standard.The results are as follows:According to the position of wheel-rail contact points,compared with the geometric contact state,the wheel-rail contact points under axial load are more dense and uniform,and the wheel-rail clearance on LM,LMB and S1002 surfaces is about 10 mm,8.5mm and 7mm,respectively.The equivalent taper of S1002 surface always keeps the maximum of the three.Compared with the latter two,the transverse movement is about 0 to 4mm.The equivalent taper of LM is smaller than that of LMB surface,and there are two intersection points between LM and LMB surface within 4mm to 8mm.The critical velocities of the vehicles matched with the three types of profiles all meet the standards when the vehicles pass through the linear track with excitation.When S1002 profile is running,the wheel flange contact occurs and the working condition is bad.In terms of wheelrail lateral force,lateral acceleration and smoothness index,the three profiles from best to worst are LM,LMB and S1002.When the vehicle passes through the curve with a radius of 150 m at low speed,the wheel rim contact appears on the S1002 type surface,and the working condition is bad.The performance differences of the other three indicators are not obvious,and each value is within the safety limit.When the vehicle passes through the curve with a radius of 800 m,there is no flange contact between the three profiles.At this point,the derailment coefficient of LMB profile is about 16% and 4% smaller than the wheel weight reduction rate of LM profile,respectively,showing obvious performance advantage in passing the curve.To sum up,the wheel-rail gap of S1002 profile is small,and flange contact is easy to occur during operation,so the comprehensive performance of the tread is poor.LM profile has better linear stability and higher critical velocity,while LMB profile has better curve passing ability and better wheelset alignment performance.In general,all the dynamic evaluation indexes of LM profile and LMB profile are within the safety standards,and can be used in domestic subway.