On freight wagon dynamics and track deterioration

To increase understanding of the running behaviour of freight wagons a research project was started at the Royal Institute of Technology (KTH) in 1996. The background to the project included plans to increase axle load, loading gauge and speed of freight trains in Sweden to make freight traffic more competitive. Simulation models for three different types of UIC freight wagon running gear were developed. The present paper focuses on track deterioration of freight wagons caused by high vertical wheel-rail forces. First the characteristics and modelling of some suspension elements are described, followed by a description of the deterioration model. Then the influence of the parameters of axle load, height of the centre of gravity and vehicle speed on track deterioration is investigated. Track parameters such as rail type and sleeper spacing are varied. The conclusion is that track deterioration per transported pay load increases when the axle load and loading gauge are increased. However, this can be compensated by using an improved track design.