Prediction of crosswind-induced derailment of train-rail-bridge system by vector mechanics

A train-rail-bridge (TRB) interaction model of vector mechanics (VM) is developed to predict the derailment of a train traveling over cable-supported bridges under crosswinds. The aerodynamic coefficients measured from the bridge section-model in wind tunnel testing is used to simulate the unsteady wind pressure acting on the train-bridge system by buffeting forces in the time domain. A versatile wheel-rail contact model considering the wheel-rail contact geometry is then formulated to assess the risk of derailment of a running train. The feasibility and effectiveness of the proposed VM-TRB model are verified by comparison with a conventional finite element procedure. To assess the running safety of the train, a two-phase plot of derailment factors for each pair of wheelsets is generated. The plots indicate that both wind velocity and train speed are critical factors that lead the train cars to potential derailment. Nevertheless, the linking railcar couplers play a holding role in reducing the separation or jumping of the moving wheels from the rail. The case study well demonstrates the capability of the VM-TRB model in dealing with train derailment.