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Annually locomotive-building plants, equipment suppliers and service companies develop organizational and technical measures aimed at improving the reliability of products. Thus, within the framework of the contract for the supply and maintenance of electric locomotives of the ERMAK series, a number of corrective measures have been implemented in more than thirty directions, many of which have achieved a positive result. However, during the long-term operation, more and more new hidden technical defects are revealed, and in rare cases, the measures taken are not enough. The manifestation of systemic inconsistencies is random in nature, thereby they negatively affect the dynamics of the average daily mileage and the linear mileage completed over the entire life cycle, causing unpredictable fluctuations, and as a result, the organization of service planning and budgeting to support the life cycle of locomotives. Therefore, there is a need to develop a model for a more accurate forecast of the average daily mileage for a long period, considering the impact of system inconsistencies and corrective measures to improve the reliability of nodes. The article uses the Pareto principle to analyze system malfunctions of locomotives manufactured by PC NEVZ LLC for the period of operation from 2018 to 2021, analyzes the dynamics of the average daily mileage of the locomotive fleet of the Far Eastern Traction Directorate with the use of a statistical and analytical method, analyzes the impact of failures on the average daily mileage using the Fourier time series forecasting method. On the example of malfunctions of power current-carrying buses of a rectifier-inverter converter and malfunctions of latches of a high-voltage vacuum circuit breaker, the influence of malfunctions of critical nodes is evaluated.

In the article it is developed a model for the locomotives life cycle managing in their maintenance and repair using automated technical diagnostic systems. Based on statistical analysis of data on the operation of locomotives, the impact of the reliability of the locomotive and its maintenance and repair system on the efficiency of locomotives is theoretically justified. A method of analyzing the technical diagnostic systems effectiveness using the mathematical apparatus of information theory and of predicting the duration of maintenance and repair time with the dynamic use of accumulated statistics on the duration of previous repairs has been developed.

In article from positions of uniform life cycle locomotives, from creation before write-off, the major factors influencing the level of their reliability are considered. Value of these factors will give the chance to connect mathematical model the potential level of reliability put in the specification on design of new locomotives with the actual reliability in specific conditions of operation and on this basis to determine the optimum parameters systems of maintenance and repair corresponding to maximum efficiency of use locomotives for all life cycle.

The article presents the equivalent circuit of three conductors, taking into account their mutual influence. The equivalent circuit contains the resistance and inductance of each conductor, the conductivity and the capacitance of their insulation relative to the earth, as well as the mutual inductances, conductivities and capacitances of the insulation between the conductors. The mathematical foundations of calculating the distribution of electrical quantities in the system of three conductors are considered, taking into account their mutual influence. An iterative incremental model of the software life cycle was chosen as the basis for automating this calculation, taking into account existing approaches to software development. Specific features of specialized software are specified. A structural scheme of the software complex and a block diagram of the calculation algorithm are proposed. The algorithm is based on the iterative calculation of currents and voltages for three conductors, taking into account their mutual influence. In accordance with the chosen model of the life cycle of the software, three versions of software with different functionality have been developed. This allowed us to effectively organize the processes of testing, debugging and implementation. As a result, the software complex has a window interface containing four tabs and allowing to enter the initial data for the calculation, display the results in the form of graphs and tables. For saving the results of calculations, a connection with the database has been implemented.

The need to apply various methods for predicting the technical condition of reinforced concrete supports of the contact network is currently a necessary condition for ensuring the safety of train traffic. Such a need arose due to the presence in operation of supports with extended service life, in the absence of a reduction in loads, without the presence of various kinds of redundancy. The article describes a method for predicting the technical state of the supports of the contact network. Solving the problem of exploitation, which consists in the fact that it is rather difficult to reveal the system of failures of the considered object of exploitation, under the influence of many factors. The probability of finding the contact network supports in a certain state is expressed through the statistical properties of the contact network supports, based on the change in the carrying capacity

Using the example of operating gas fields in the Western Siberia, the issue of the correct choice of voltage class, considering all the periods of gas fields life cycle, appears. Wrong choice of the voltage class leads to braking development of a gas field. Gas field technological scheme during the each period of the life cycle is considered, the dynamics of the electrical load is estimated. The analysis of existing methods of choosing the voltage class is carried out and their flaws are revealed. Mathematical models of the optimal voltage class calculation and discounted costs calculation are developed using the theory of experiment planning. An algorithm of choosing the optimal voltage is developed and the distribution and supply networks of the external power supply system of the existing gas fields in Western Siberia are investigated. Progressive voltage class for power supply and distribution network is proposed. Conclusions are made.