Measurement of rolling-sliding wheel/rail contact condition using full-scale rig with ultrasound

This paper describes the measurement of the rolling-sliding contact condition between wheel and rail using ultrasound waves. Unique experiments were performed using a full-scale dynamic wheel/rail contacttesting machine and an ultrasonic array transducer. The ultrasonic array transducer provides a 2D measurement of dynamic interfacial stiffness. It was found that the running-in transitions of traction coefficient and contact stiffness were significantly influenced by the initial surface roughness. Contact stiffness appears to have an almost linear positive correlation with the traction coefficient. These findings might inform rail service providers about optimal wheel profiling methods to reduce the likelihood of wheel climb derailment.