Technological model for organizing efficient maintenance of signaling and interlocking devices on low‑intensity railway sections

<jats:p>Background. The relevance of the study is due to the need to optimize operating costs for the maintenance of signaling and interlocking devices on low-intensity railway sections. Such sections, characterized by freight intensity of less than 15 million tkm/km per year, constitute a significant part of the network of the Russian Federation. However, traditional scheduled preventive maintenance systems, designed for intensively operated lines, lead to unjustifiably high unit costs, a mismatch between the frequency of maintenance and the actual aging rate of equipment, and an excessive number of personnel trips. Current trends require a transition to condition-based maintenance using predictive analytics methods. The lack of comprehensive technological models adapted to the conditions of low-intensity sections determines the need to develop a scientifically based approach that ensures a balance between economic efficiency and the required level of traffic safety. Purpose. Development of a technological model for organizing efficient maintenance of signaling and interlocking devices on low-intensity railway sections, based on the principles of failure prediction and rational resource allocation, allowing to reduce operating costs while maintaining or improving reliability and traffic safety. Materials and methods. The research is based on a statistical analysis of 2,348 records of failures of signaling and interlocking devices on low-intensity sections for the period 2020–2023, classified by device types and nature of malfunctions. To describe the patterns of failure occurrence, a modified Weibull distribution was applied, taking into account seasonal fluctuations and operation intensity. Nonlinear and dynamic optimization methods were used to determine rational maintenance intervals. A simulation model of the maintenance system was developed, and 2,000 runs were performed for various scenarios (confidence probability 95%). Economic efficiency was assessed using discounted cash flow methods (NPV, IRR, payback period). The initial data for the calculations correspond to a typical low-intensity section 50 km long with a specific list of devices and work costs. Results. The proposed technological model, including a differentiated approach to maintenance by criticality classes and an algorithm for optimizing maintenance intervals, allows to increase the average maintenance interval by 57.8% (from 90 to 142 days), reduce the number of unscheduled failures by 38.9%, and decrease the average recovery time by 45.2% (according to calculation results). The system availability factor can increase from 0.980 to 0.991, which corresponds to a reduction in downtime by 55%. Annual operating costs can be reduced by 20.5% (2.7 million rubles for a 50 km section) with an estimated payback period for capital investments of 1.6 years. The developed models and recommendations can be replicated on other low-intensity railway sections.</jats:p>