A prolonged short circuit in the third-rail power system of Washington, D.C.’s Metrorail system has been determined to be the probable cause for a January 2015 electrical arcing and smoke incident that killed one passenger and injured dozens more, the National Transportation Safety Board (NTSB) said on May 3.
In announcing the findings of its 15-month investigation of the incident, which occurred in a tunnel adjacent to the L’Enfant Square station, the Board faulted the Washington Metropolitan Area Transit Authority (WMATA) for “ineffective inspection and maintenance practices” that created conditions for electrical arc tracking to occur in a 16-ft long jumper cable. Investigators said the arc tracking was aided by the presence of contaminants and moisture on third-rail cables and inside cable connector assemblies, which were found to have been lacking required sealing components.