Determination procedure of actual drive wheel–rail contact area for railway vehicles

Abstract

The main function of the wheel–rail system is to ensure the transmission of torque from the wheel to the rail, and to ensure the appropriate traction of the locomotive. Numerous studies have shown that the contact of real rough surfaces is discrete, i.e. random, due to the interaction of individual protrusions of micro-surfaces. Modern science of friction states that when roughness is randomly located on the surfaces of contacting bodies, the contact convergence of these bodies under load determines the actual contact area dependent on the geometry of the contacting surfaces. The friction force in the contact zone is governed by the sum of the friction forces at individual points of interaction. Therefore, the total friction force depends on the actual contact area of the contact surfaces. Therefore, determining its actual value, which is a parameter that ensures the performance of railway transport, is a priority and urgent task. This paper presents a method for calculating the actual contact area, which allows determining the expected value of the traction force in the contact zone of the locomotive wheel with the rail. The application of the results of these studies in maintenance of rail tracks during operation makes it possible to conclude that an accurate determination of the actual contact area can reduce the contact stresses when the wheel and rail surfaces interact by almost 1.9 times.