Assessing rail freight reliability under mixed-traffic conditions: The role of capacity allocation and traffic management policy

The reliability of rail freight on mixed-traffic lines in Europe has become an increasingly critical issue in achieving modal shift objectives. However, current knowledge about service reliability risks on such lines remains limited, and existing practices fail to address vulnerabilities stemming from heterogeneous dispatching priorities. This study examines the prevailing capacity allocation and traffic management practices on mixed-traffic lines to identify sources of reliability risks. Based on these findings, the study proposes a method to quantify reliability risks through an ex-post assessment using realized operational data. The method is applied to a case study focusing on the Swedish section of the Scandinavian-Mediterranean freight corridor. A micro-simulation model is employed as the source for realization data, exploring scenarios with different prevailing traffic management policies, variations in planned top speeds for freight services in mixed traffic conditions, and cases with enhanced train dynamics. The results show that adopting a real-time traffic management policy that considers the punctuality of conflicting trains as a criterion can, under certain conditions, reduce freight reliability risks. However, path planning practices, particularly when resolving scheduling conflicts, remain the dominant factor compromising service reliability. The proposed approach demonstrates its value as a decision-support tool, equipping policymakers and traffic planners with the means to assess freight reliability risks and refine their strategies accordingly.