Paper 1: The Dynamics of Railway Vehicles on Straight Track: Fundamental Considerations of Lateral Stability

Abstract

The dynamics of existing railway vehicles on straight track is dominated by motions in the lateral plane commonly referred to as hunting. Hunting is a self-excited oscillation caused by the combined action of the conicity of the wheels and the creep forces acting in the contact plane between wheel and rail. In this paper existing and recently developed theories of the lateral motion of railway vehicles are discussed in relation to experimental work on both models and full-scale vehicles. It is shown that a realistic theory taking into account flexibility between the wheelsets and the frame in the longitudinal, lateral, and vertical directions, and the influence of wheel and rail profiles, yield values for the critical speeds which are consistent with experimental results. The influence of various parameters on stability is discussed and it is explained how railway vehicles can be designed for stable running at high speeds. Examples of suitable choices of suspension and other parameters will be given and experiments carried out in order to verify these concepts will be described.