<p>The article presents a mathematical model of the wear of contact strips of pantograph which is destined to define a diagnostic parameter for determining pantograph of the freight electric locomotives in the Republic of Uzbekistan. Existing mathematical models of pantograph - contact network interactions are considered in the form of multidimensional models with reduced masses. The Matlab - Simulink tools can be used for solving the mathematical models. Computer programs for solving mathematical models enable efficient calculations at high accuracy. During the simulation, the current pantograph-contact network system was considered as a two-dimensional model with two degrees of freedom. The simulation results helped determine the diagnostic parameter of the “vibration acceleration” of the contact strips. Finding a diagnostic parameter is based on vibrational movements of the pantograph skid interacting with the contact <br /> network.</p>