Investigation on braking tribological properties of metro brake shoe materials

The objective of this study is to investigate the braking tribological characteristics of two kinds of metro brake shoe materials using a sub-scale frictional braking machine. The results indicate that the friction coefficient of braking interface has a close relationship with the velocity and pressure. The increase of velocity and pressure raises the temperature-rise of braking interface. The increasing velocity and pressure aggravate the wear of brake shoe rings. However, the wear loss of wheel rings decreases with increasing pressure. The braking surface of brake shoe rings exhibits adhesive wear and spalling, while obvious plowing and abrasive wear are dominant on the braking surface of wheel rings. According to the experimental results, it is concluded that brake shoe B material can be used to prevent and alleviate the occurrence and evolution of groove wear on wheel tread. This might be attributed to the higher percentage of FeC3 versus FeS2 in its composition compared with brake material A. Field testing, completed to 100,000 km thus far, has to be completed on these materials and further work should be performed for evaluating the effect of different brake shoe materials on the groove wear of wheel tread in the field.