Influence of the coupler and buffer device on the train collision safety

Based on the multi-body dynamics the three-dimensional train collision model including a more detailed coupler-buffer substructure is established in this paper. During the train collision, the dynamic responses of the coupler-buffer substructure are comprehensively analysed. Some key parameters, such as the coupler initial deflection angle, max-angle, plunger spring stiffness and buffer impedance force, are investigated and their effects on the train derailment are also evaluated. According to the simulation results it is indicated that at present the coupler-buffer device is designed mainly from the point of view of the normal operation condition. Compared with the normal operation, in the train collision condition the longitudinal impact force is so large that the coupler-buffer device reveals a very weak ability to anti-jackknifing. As a result, in most cases the coupler rotation angle is very large and equal to its designed max-angle. Under the effect of this large coupler rotation angle, the collided trains have a high risk to derail. The importance of the anti-jackknifing of the coupler and buffer device is illustrated in this paper, which has a great influence on the train collision safety and should not be neglected. In order to improve the safety against derailment, it is suggested to decrease the coupler’s max-angle and increase its plunger spring stiffness. Alternatively, a friction arc coupler yoke connection design is suggested to replace the current coupler yoke design.