Aging Rail Infrastructure Sparks Safety Concerns for Light Rail and Subway Transit

The National Transportation Safety Board (NTSB) has issued a safety alert highlighting critical failures within the nation’s aging electric propulsion power systems, which pose increasing risks to passengers and employees. Investigations by the NTSB have identified a pattern of electrical arcing, fire hazards, and smoke incidents stemming from these failures. These issues are becoming more prevalent as the country’s rail infrastructure ages and, in some instances, incorporates newer technologies alongside legacy components.

The NTSB’s findings point to several contributing factors that can lead to dangerous situations on the rails. Issues such as flooding or inadequate drainage can expose electrical cables to moisture, accelerating the degradation of their insulation. Additionally, worn components like collector shoes on third-rail systems or pantograph heads on overhead catenary systems can result in intermittent contact and electrical arcing. Furthermore, loose or corroded electrical connectors and joints within both third-rail and catenary systems can increase electrical resistance. This heightened resistance can generate excessive heat, leading to fires, electrical shorts, and other severe safety hazards.

Recent NTSB investigations have also revealed that some transit and commuter rail operators are attempting to integrate modern technologies with older, existing infrastructure. This can introduce unforeseen failure modes that were not present with the original equipment. Temporary repairs, undocumented modifications to third-rail or catenary systems, and the natural drift of aging electrical component tolerances away from their original design specifications can all exacerbate these problems. These issues can manifest as arcing due to worn contact surfaces, fires caused by compromised cable insulation, and overheating from compromised electrical connections. The safety alert emphasizes that existing maintenance and inspection plans at many transit and commuter rail agencies may not be sufficient to adequately detect or mitigate these critical failures. Visual evidence from investigations includes damaged third-rail feeder cables in Jersey City, New Jersey, a train in Dallas, Texas, making contact with a low overhead catenary wire, and internal damage to a railcar in Ridley Park, Pennsylvania, following a fire.

To address these growing concerns, the NTSB recommends that railroads and rail transit agencies implement robust reliability engineering processes. These processes should be used to re-evaluate the safety analyses of electric propulsion power systems and other critical components, particularly as equipment ages and when changes or repairs are made. Agencies are urged to ensure that all identified hazards, including those associated with aging electrical infrastructure or new replacement parts, are integrated into their system safety programs, such as Safety Management Systems (SMS). An SMS provides a structured framework for evaluating potential failure modes of new or modified components, ensuring their safe integration with existing systems, and establishing ongoing monitoring to identify and mitigate emerging risks effectively.

Furthermore, the NTSB advises operators to be vigilant regarding electric propulsion power system failures that involve aging electrical components. This includes a thorough review of current maintenance, testing, and inspection procedures for all associated electrical systems, both trackside and on-board railcars, and prompt action to rectify any identified deficiencies. The safety alert also stresses the importance of utilizing knowledge gained from past system failures, documented in incident records or investigation findings, to revise or develop comprehensive maintenance, inspection, and testing procedures designed to detect or prevent these types of failures. To proactively identify and manage safety issues, agencies are encouraged to leverage technology that can generate real-time trend reports, allowing for early detection of emerging safety concerns and timely risk mitigation.

Article by Mel Anara, based upon information from the National Transportation Safety Board.

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