Functions of wheel-rail contact geometry

Abstract

The running of railway vehicles is based on the interaction of wheelset-track or wheel-rail with precisely defined nominal geometries. In this way, the geometric relationships which allowing smooth running in tangent and curved track are achieved. However, geometries in practice deviate from nominal to a greater or lesser extent. This cause the constant change of geometric relationships between wheels and rails and all dynamic parameters of railway vehicles during the running. For this reason, the modelling of wheel-rail contact geometry is very important task in rail vehicle dynamics. This paper gives a systematic approach to the analysis of wheelset-track and wheel-rail contact geometry. After introducing the parameters of wheelset and track geometry, the non-linear geometric relationships between wheel and rail profiles are analysed, and parameters of wheel-rail contact geometry are defined. In final stage, the functions which combines all analysed parameters are derived. A special discussion about the equivalent conicity as the most important function of wheel-rail contact geometry is given. The methods of its determination and influence on the dynamic behaviour of wheelset and vehicles are discussed. Considerations in the paper confirm the fact that wheel-rail contact geometry and equivalent conicty as function which representing it, play one of the most important role in dynamic behaviour of railway vehicles.