Location Optimization of EMU Maintenance Bases Considering Minimization of Service Area Overlap

To address the capacity shortfall in high-level maintenance of Electric Multiple Units (EMUs) and meet the growing maintenance demand, the location of maintenance bases must be optimized. To avoid resource waste, this paper introduced a repulsion formula between bases based on Coulomb’s Law, aiming to minimize the overlap of maintenance service areas. Only bases with the appropriate qualifications for specific train types and maintenance levels can undertake the corresponding maintenance tasks. Accordingly, a maintenance matching formula was developed to quantify this relationship. From the perspective of multi-project economic evaluation, an investment selection model for EMU maintenance bases was established to minimize the total system cost, which includes the annualized construction investment cost, round-trip empty running cost, high-level maintenance cost, and maintenance capacity loss cost. By minimizing service area overlap and optimizing maintenance task assignments, the model helps to reduce empty running mileage, improve facility utilization, and avoid asset idleness, thereby contributing positively to enhancing resource intensification and operational resilience of the railway maintenance network. Taking the Chinese regional railway network as an example, Gurobi was employed to solve the optimization model. The results show that expanding the bases in Chengdu and Guangzhou, and building a new maintenance base in Nanning minimizes the annualized total cost within the planning period. Cost composition analysis reveals that annualized initial investment accounts for only a small proportion of the total cost, while high-level maintenance cost dominates, indicating that the core benefit of location optimization lies in reducing long-term operating costs and improving resource utilization efficiency.