SASTech - Technical Journal of RUAS

Wheel tread defects cost international railway industry several hundred millions of dollars annually for the repair and replacement, affecting freight and transit system alike. Based on their initiation mechanism, these defects can be classified as cracking, spalling and shelling.

In this study, the specific problem of wheel tread defect, observed in LHB coach wheel, was investigated. The problem was observed after the change in braking system from tread braking to disc braking. The problem identified was spalling damage and investigation was carried out to determine effect of braking system on wheel spalling. In this work, a multibody parametric model of a LHB coach was simulated using ADAMS/Rail and the rail wheel contact dimensions were determined. After studying the rail wheel interaction, different mathematical models were utilised to calculate sliding velocities and interface temperature rise in the wheel during sliding. A Finite Element (FE) Model was developed for computation of temperature field in the wheel. Using this information and its effect on resulting phase transformation in the wheel material, the extent of damage was computed.

The outcome shows that the wheels with disc brakes have more tendency to slide due to higher braking force. High temperature generated at the rail-wheel interface during sliding causes the wheel to spall. The extent of damage was found to be dependent on sliding duration and the interface temperature.