The behavior of the Coupler in the Train

A fundamental demand for all construction units in a train is to maintain safety against derailment under each possible condition. Concerning the derailment safety centre couplers are critical if the train comes under pressure - this is the case during braking. High compression forces in the train arise, if the rear vehicles brake later. In this case rear vehicles run at front vehicles. Under certain conditions upward force-components arise, which, if these exceed the weight, can lead to derailing. Under the conditions of with the well-known side buffers the danger of such situations was very little because the high frictional forces between the buffer plates. But in case of trains with automatic couplers a vertical upwards component results at a higher vehicle and derailment follows if this component exceeds the weight of the higher vehicle

Under the critical view of high-speed cameras such derailing situations have been simulated with real vehicles.

By the use of a so called 'stabilization end ' of the coupler these critical forces could be reduced to an uncritical level. Helpful was the development of computer-programs, which could simulate practical combinations and calculate the forces at the vehicles with high reliability.