The critical speed of a railway vehicle on a roller rig

The dynamic behaviour of a railway vehicle is largely governed by the inter action 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 p aper 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 b ecomes unstable has been shown to differ between the vehicle on track and o n 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.