PREDICTION OF THE THERMAL STABILITY OF WHEEL UNDER FREQUENT BRAKING FOR URBAN RAIL VEHICLE

A train is braked to stop when it reaches every station in an urban rail transit network. The combination of electropneumatic braking is currently adopted for many trains in China. The electric braking is manipulated prior to pneumatic braking. In the case of electric braking failure, the pneumatic braking device will then be used to perform ultimate protection. A typical pneumatic braking device includes a wheel and brake shoe. The work status of the wheel will certainly affect the running of train in frequent braking. In this paper, the authors established a three-dimensional finite element model (FEM) of wheel to simulate the three-dimensional transient temperature fields of the wheel at different running velocities and braking deceleration conditions. In addition, we analyzed the thermal stability of the wheel. Finally, we calculated the safety-related running velocity and braking deceleration. The results of the calculation are aimed to provide useful guidance for the urban rail operation in Chinese major cities. We recommend that the urban train speed should be lower than 60km/h when only the pneumatic braking device is used for braking.