The article examines economic and managerial mechanisms for improving the efficiency of service maintenance of high-speed rolling stock under conditions of accelerated growth of operating costs and tightening requirements for traffic regularity. It is shown that a significant share of the life-cycle cost of high-speed trains is formed by expenses for maintenance and repairs, while inertial adherence to the regulations of the planned preventive system simultaneously generates overspending of resources on routine operations and the risk of sudden failures with substantial direct and indirect losses from downtime. Based on the decomposition of costs by business processes and statistical analysis of a dataset of managerial and technical data for 2018–2023, structural shifts in the expenditures of service depots were identified: over a three-year interval, total operating costs for servicing a unit of rolling stock increased by 15.69%, while expenditures on emergency recovery repairs rose by almost 40%, and their share increased from 8.96% to 10.84%, which is interpreted as an indicator of reliability degradation and insufficient effectiveness of preventive measures. A comparison of the traditional maintenance strategy with pilot implementation of condition monitoring and predictive analytics demonstrates a sharp reduction in on-line failures and a decrease in downtime duration, despite a multiple increase in diagnostic and software costs; the overall economic outcome improves due to a reduction in lost revenue and direct expenses for failure elimination. A significant efficiency reserve is identified in inventory management: application of the ABC–XYZ approach makes it possible to release 22.05% of capital, increasing average turnover from 2.87 to 3.98. Sensitivity analysis of the investment profitability of repair base modernization shows the greatest dependence on operating intensity and the cost of imported components, which simultaneously captures the effect of scale and currency-inflation risks. Comprehensive implementation of service digitalization, inventory optimization, and equipment renewal ensures a reduction in the cost of servicing a kilometer of mileage by 16.23% and achievement of a technical availability coefficient of 0.97; at the same time, a threshold efficiency of additional investments in diagnostics is established, and the need to synchronize technological measures with the restructuring of personnel motivation toward fleet readiness indicators is emphasized.