Climate change impacts on railway operations: Spatial risk assessment based on rail temperature and operation frequency under SSP scenarios

Climate change is expected to have significant impacts on the operational safety and reliability of railway systems. As extreme heat events become more frequent and intense, elevated rail temperatures can lead to speed restrictions or service suspensions, posing challenges to the stability and efficiency of rail operations. In this context, this study quantifies the impacts of climate change on rail operations in South Korea by simulating rail temperature changes and assessing abnormal operation days under two climate scenarios: SSP 126 and SSP 585. Specifically, daily maximum air temperature data (2021 ~ 2100) were obtained from the Korea Meteorological Administration, and rail temperatures were derived using an empirical linear function. Based on these estimates, and according to rail operation guidelines, days with restricted operations (≥ 55°C) and service suspensions (≥ 64°C) were identified for each rail line and segment. Under SSP585, operational restrictions are projected to increase significantly after the 2050s, with some segments experiencing more than 80 restricted days annually. Moreover, vulnerable areas include inland cities such as Daegu and Gwangju, while metropolitan corridors like the Gyeongbu Line face considerable risk due to high train frequencies. By integrating thermal exposure and train operation density, this study provides a comprehensive assessment of railway climate vulnerability. Overall, the findings underscore the necessity for targeted adaptation strategies, including thermal mitigation measures, real-time temperature monitoring, and region-specific maintenance planning.