Semi-quantitative Risk Assessment of Adjacent Track Accidents on Shared-use Rail Corridors

Safety is a high priority for any rail system, and there are several safety concerns associated with operating passenger and freight trains on shared-use rail corridors. Adjacent track accident (ATA) is one of the most important concerns. ATA refers to train accident scenarios where a derailed equipment intrudes adjacent tracks, causing operation disturbance and potential subsequent train collisions on the adjacent tracks. Other ATA scenarios include collisions between trains on adjacent tracks (raking), turnouts, and railroad crossings. Limited literature is available that addressed the risk of ATA for shared-use rail corridors. The research described in this paper presents a comprehensive risk assessment to identify factors affecting the likelihood and consequence of adjacent track accidents. A discussion on how these factors affect the probability, consequence, and how individual factor relates to each other are provided. A semi-quantitative risk analysis is developed to investigate various factors affecting train accident rate, intrusion rate, and accident consequences. This research intends to depict a high-level overview of adjacent track accidents and provides a basis for future quantitative risk analyses and risk mitigation implementations. NOMENCLATURE ATA: Adjacent Track Accident CFS: Consequence Factor Score FRA: Federal Railroad Administration IFS: Intrusion Factor Score NTSB: National Transportation Safety Board SRC: Shared (or Mixed) Use Rail Corridor TPS: Train Presence Score INTRODUCTION Shared-Use Rail Corridor A large number of developments of improved or expanded passenger rail service in the U.S. involve the use of existing railroad infrastructure or rights of way (1). Shared or Mixed Use Rail Corridors (SRC) refer to different types of passenger and/or freight train operations using common infrastructure in one way or another (2). Figure 1 shows three types of SRC: shared track, shared right-of-way and shared corridor, defined by the U.S. Department of Transportation, Federal Railroad Administration (FRA). Figure 1 Definition of SRC by FRA (3) Adjacent Track Accident (ATA) A number of safety, infrastructure, equipment, planning, operational, economic and institutional challenges have been identified for the implementation of SRC (1). Safety is a high priority for any rail system, and there are several safety concerns associated with operating passenger and freight trains on SRC. Adjacent track accident is one of the most important concerns (1). ATA refers to train accident scenarios where a derailed equipment intrudes adjacent tracks, causing operation disturbance and potential subsequent train collisions on the adjacent tracks. Other ATA scenarios include collisions between Proceedings of the 2014 Joint Rail Conference JRC2014 April 2-4, 2014, Colorado Springs, CO, USA