Effects of train speed, track irregularities, and wheel flat on wheel-rail dynamic forces

Abstract

Today, the wheel-rail dynamic forces (WRDFs) is one of the criteria for reliable evaluation of running stability, track loading, and vibration behaviour of railway systems. Over-limit dynamic forces, with the creation and growth of wheel and rail defects, are the cause of the derailment, accidents, and damage, and must be constantly monitored. In the present paper, after modelling and validating a passenger rail system, the effects of changes in train speed, track irregularities, and wheel flats on the WRDFs, derailment coefficient, and wheel-rail dynamic impact factor are evaluated. One of the results showed that by changing the train speed in different track irregularities, the WRDFs has changed significantly and the maximum force has increased with increasing speed. For example, in class 5 and class 6 of irregularity, by changing the train speed from 20 km/h to 100 km/h, the WRDFs is increased about 32% and 27%, respectively.