Currently, the urgent task is rapid pre-determine the need for freight train locomotives in the rail transport of countries of the world. The purpose of the research work is to determine the demand for train locomotives, taking into account the weight standards of freight trains. To check the reliability of the results obtained, as an example, the use indicators for railway precinct A-V of electric locomotives were analyzed. An algorithm for determining the used fleet of electric locomotives necessary for servicing freight trains has been developed. The fleet of electric locomotives has been determined step by step necessary for the service of freight trains on the conditional railway section.