Influence of wheel tread wear on Rolling Contact Fatigue and on the dynamics of railway vehicles

This paper evaluates the influence of railway tread wear on the occurrence of Rolling Contact Fatigue (RCF) as well as other dynamic parameters of the railway vehicle in order to propose a tread maintenance limit. Around 160 unworn and worn AAR-1/20wheel profiles were measured and simulated inside the commercial software UM (R) -Universal Mechanism on a representative track segment of a Brazilian railway. With the simulated dataset, RCF was evaluated using the Shakedown Diagram, the Energy Dissipation Model, and the Wheel Gauge Side False Flange Gradient. Vehicle dynamics were assessed using the Nadal Criterion, contact pressure, and Rolling Resistance. The results show when the tread wear depth exceeds 2.0 mm, RCF is very likely to occur due to larger contact pressures. However, no clear relationship between tread wear, safety (Nadal Criterion), and fuel expenditure were observed. Therefore, this study suggests keeping wheelsets in service until a tread wear depth of 2.0 mm occurs in order to avoid RCF.