On September 25, 2025, about 6:58 a.m., westbound Southeastern Pennsylvania Transportation Authority (SEPTA) Trolley 111 was operating on main track 2 of the D1 Line at milepost 3.97 with nine passengers and an operator onboard in Springfield, Pennsylvania, when its pantograph became entangled with the overhead catenary system. A portion of the pantograph separated from the trolley car, and components of the pantograph penetrated the trolley’s roof and entered its passenger compartment. The trolley operator and three passengers requested transport to a hospital for minor injuries.
We determined that the probable cause of the September 25, 2025, accident was Southeastern Pennsylvania Transportation Authority’s (SEPTA) lack of a formal inspection and maintenance program for its overhead catenary system (OCS), which led to SEPTA failing to identify and correct unsafe catenary conditions that caused the pantograph on Trolley 111 to become entangled in the catenary wires and separate from the trolley, and caused pantograph components to penetrate the trolley’s passenger compartment.
Contributing to the accident was Pennsylvania Department of Transportation State Safety Oversight Agency’s failure to require SEPTA to implement a formal and enduring OCS inspection and maintenance program after they identified SEPTA’s inadequate OCS inspection and maintenance activities.
Rail transit agencies are required by Title 49 Code of Federal Regulations Part 673 to have safety assurance processes that ensure maintenance procedures are sufficient and being complied with. To prevent similar accidents in the future, rail transit agencies and state-safety oversight agencies should ensure that formal inspection and maintenance programs for all infrastructure and rolling stock assets, including traction power systems such as overhead catenary and third rail systems, are sufficient and that adherence to those programs is maintained. Effective inspection and maintenance programs include explicit inspection frequencies, defined defective conditions, and required remedial actions for each defective condition. To ensure these programs continually meet organizational safety goals, adapt to new technologies and operational changes, and avoid a normalization of deviance, it is critical that they include procedures for monitoring the program’s effectiveness and verifying employee compliance with it.
In addition to rail transit agencies, electrified heavy-rail passenger railroads should similarly ensure that formal inspection and maintenance programs are in place for all infrastructure and rolling stock assets, including traction power systems like overhead catenary and third rail systems. To call attention to risks posed by aging electric propulsion power systems in both rail transit and heavy rail, in March 2026 the NTSB published a safety alert encouraging railroads to review and address deficiencies in traction power electrical system procedures and maintenance and to incorporate electrical hazards into system safety programs.
