NTSB preliminary report of WMATA smoke incident focuses on 'severe electrical arcing'

The National Transportation Safety Board (NTSB) on Friday released a preliminary report on last week's deadly incident involving a smoke-filled train on the Washington Metropolitan Area Transit Authority's (WMATA) Metrorail system.

One rider died in the Jan. 12 incident, which occurred near WMATA's L'Enfant Plaza Station in Washington, D.C.

NTSB investigators said train No. 302 stopped when it encountered heavy smoke filling the tunnel for southbound trains. A following train also stopped. Passengers of both trains, as well as those waiting on station platforms, were exposed to heavy smoke. Eighty-six riders were transported to hospitals for treatment.

After inspecting the area, investigators observed severe electrical arcing damage to the third rail and electrical cables about 1,100 feet ahead of train 302. Recorded data showed that an electrical breaker at one end of a section of third rail tripped at about 3:06 p.m. At about 3:16 p.m., the WMATA Operations Control Center (OCC) began activating fans to exhaust smoke from the area, the report states. The electrical breaker at the other end of the third rail section remained closed; supplying power until the WMATA OCC remotely sent a command to open the breaker at about 3:50 p.m., the report states.

The NTSB is continuing its investigation, which is being assisted by the Federal Transit Administration, WMATA, the Tri-State Oversight Committee, Amalgamated Transit Union Local 689, and the Bureau of Alcohol, Tobacco, Firearms and Explosives.