Friction at the Wheel-Rail Interface

Performance of the vehicle-track system is governed by the way the vehicle load transfers to the rail through small contact patches at each wheel. Wear, fatigue, instability, and noise are all the consequences of the performance of the wheel/rail contact, which in turns is controlled by 4 sets of properties: 1) wheel-rail contact geometry; 2) material properties; 3) dynamic characteristics of the vehicle and track; and 4) friction characteristics of the wheel/rail interfacial layer. This article focuses on the 4th item, friction, and explains how an increasing dependency on numerical simulation brings greater urgency to the need to properly measure and implement friction models.