The critical speed of a railway vehicle on a roller rig

The dynamic behaviour of a railway vehicle is largely governed by the interaction of the wheelset with the track. This behaviour can be reproduced in a laboratory using a roller rig and can also be mathematically simulated by solving the equations of motion which govern the dynamic behaviour. This paper presents the results of a study that compares the predictions of these equations of motion for a one-fifth scale railway vehicle on track and on a roller rig. In particular, the critical speed at which the motion first becomes unstable has been shown to differ between the vehicle on track and on the roller rig. It has been shown that for most cases the roller rig case has a lower critical speed but for some suspension parameter combinations the critical speed on the roller rig can be higher.