Track settlement prediction using computer simulation tools

A project is being carried out at Manchester Metropolitan University to examine the effects of different vehicles on track deterioration and consequent maintenance costs. A number of track settlement models have been investigated including those published by Prof. Sato in Japan and a model based on laboratory experiments,at the Technical University of Munich. The MEDYNA simulation package has been used to generate the equations of motion for the vehicles being studied and time stepping integration routines used to predict motions and forces as required. The, ADAMS/Rail package has also been used to assist with the visualisation of the models and the predicted behaviour. Inputs to the model were made at each wheelset. These were either idealised discrete events such as dipped rail joints or measured values from real sections of track. The results are presented here for three vehicles with different types of suspension and for two of the track settlement models. All of the settlement models used predict that the suspension characteristics have a large effect on the rate of track deterioration. The general trends in predicted track settlement rate agree between the two settlement models but there are also,some very significant variations in the relative rates for some cases.