Scale Efficiency Impact of Increasing Rolling Stock Operations to Relieve Passenger Congestion using DEA: Focusing on Seoul Urban Railway Line 2

High passenger congestion on urban railways significantly reduces the quality of transportation services. A representative method to relieve high congestion is to increase operation. However, increased operations may lead to varying outcomes from a maintenance operations perspective. In this paper, researcher used DEA to analyze changes in technical efficiency, pure technical efficiency, scale efficiency, and return to scale to confirm changes in maintenance efficiency due to increases in rolling stock operation to relieve high congestion of Seoul Metro Line 2. The analysis results confirmed that increasing operation to relieve congestion increased scale efficiency. However, at the same time, the return to scale of 55% of rolling stock changed from IRS to DRS status. These results imply that as operational scale increases to relieve congestion, maintenance operational efficiency does not maintain the same rate of return. Therefore, from the perspective of maintenance operations, the results imply that excessive operational increases may lead to inefficient resource allocation, surpassing the optimal level of investment.