Purpose: High–speed railway lines (HSRL) are the most promising direction of railway transport development in the 21st century, increasing the mobility of the population at a distance of up to 1000 km, contributing to the development of urban conglomerations. Reliable rolling stock is necessary for the functioning of the HSRL. The article describes the performed mathematical simulation of the operation and maintenance and repair system (MRS) of high-speed electric trains in relation to the St. Petersburg — Moscow landfill. The purpose of the simulation is to substantiate the requirements for MRS, including when using on-board automated systems for technical diagnostics. Methods: It is based on the principles of passenger traffic organization, technical requirements for domestic high-speed rolling stock, queue theory methods, as well as probabilistic mathematical modeling methods in MS Excel in the algorithmic language Visual Basic for Applications (VBA). The corresponding software has been developed. Results: A mathematical model and software have been developed, multifactor modeling has been performed, the degree of failure impact on the required fleet of high-speed electric trains has been determined. Methods of optimization of maintenance to reduce the required fleet are proposed. The requirements for the mathematical model itself are defined. A factor analysis of operation and maintenance has been performed by mathematical modeling. Practical significance: The guarantee of safe and reliable high-speed traffic is the creation of a modern system of maintenance and repair of rolling stock. The study of the interaction of operation and maintenance is very important in preparation for the launch of domestic high-speed traffic.