Passengers board a subway train at the L'Enfant Metro Station, which is part of the public mass transit network for Washington, Tuesday, Jan. 13, 2015. The transit network in the nation's capital, remains hobbled after an electrical malfunction that filled a L'Enfant Metro subway station with smoke, killing one woman and sending dozens of people to hospitals. The NTSB is investigating the incident, which happened at the beginning of the Monday afternoon rush hour. It led to the first fatality on Washington's Metro system since a 2009 crash that killed eight passengers and a train operator. NTSB investigator Michael Flanigon told reporters that an electrical "arcing" involving the high-voltage third rail led a train to stop in a tunnel and filled the tunnel with smoke. An arcing occurs when electricity from the third rail comes into contact with another substance that conducts electricity, such as water. (AP Photo/Pablo Martinez Monsivais)
