Abstract: The collision simulation between a city tram and an automobile at the level crossing is carried out based on the multi-body dynamics. Compared with the finite element method this method has an obvious advantage of fast computation speed, so that it is convenient for the study on the dynamic behaviour of railway vehicles during a collision accident. Simulation results indicate that when the city tram is impacted laterally by an automobile with a speed of 20 km/h, the lateral movement of the impacted city tram is in priority and the roll movement is relative small. At the same time the maximum derailment coefficient of the city tram is 1.63, exceeding the limit (1.2) defined in the standard GB5599-1985. That means the collided city tram has a high risk to derail. Besides that, when the first or the last vehicle of the city tram is collided by the automobile, the lateral impact load can be transmitted to the adjacent vehicle by only one side, which results in a high derailment coefficient. Moreover, in terms of the space limitation of the city tram, two measures are proposed to decrease the lateral impact load during the transition from car body to the wheel set. One is using the secondary damper and another is increasing the secondary lateral clearance. The simulation results point out that the derailment coefficient of the improved city tram can be reduced by 52%, from 1.63 to 0.79.

Key words: automobile, city tram, collision, derailment, level crossing