Modeling of wheel and rail slip and demonstration of the benefit of maximum adhesion control in train propulsion system

This paper presents an introduction toward train movement as well as relationship among wheel and train´s speeds, and defines the notion of wheel slip including two different operation regions designated as creep and wheelspin areas holding stable and unstable characteristics, respectively. Since the equations of movements must be solve simultaneously, the model of wheel and slip is derived by integrating the corresponding equations of movements. Besides, the block diagram of train´s speed control is shown in this paper. As wheels and rails are constructed from iron, the friction among them is weak. Consequently, the operation point of speed control system may be in either creep or wheelspin areas regarding the values of driving torque compared to the value of maximum adhesion torque. Simulation results demonstrate the advantages of maximum adhesion control in train´s propulsion system minimizing the acceleration time as well as the wheel and rail sublation.