One dead as smoke hits US subway
The transit network in the US capital has been crippled by an electrical malfunction that filled a busy subway station with smoke, killing one woman and sending dozens of people to hospital.
The National Transportation Safety Board is investigating the incident which happened at the beginning of the Monday afternoon rush hour and led to the first fatality on Washington DC's Metro system since a 2009 crash 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 quickly 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.
While there was water in the tunnel, Mr Flanigon said the cause of the arcing was not yet known.
Witnesses described a chaotic scene aboard the train as passengers tried to escape the smoke, and many passengers left the train on their own before emergency responders arrived on the scene.
In addition to the woman who died, at least one other passenger was in critical condition at a local hospital. Eighty-four people were taken to hospital, most with smoke inhalation, authorities said.
The accident occurred on a Virginia-bound yellow line train that had just left L'Enfant Plaza, one of the system's busiest stations.
The Metrorail system, which connects Washington city centre with the Maryland and Virginia suburbs, carries an average of 721,000 passengers each weekday.
Smoke and fire are not unusual on the ageing subway system, which opened in 1976 and still uses some original rail carriages. Metro's most recent quarterly safety report showed 86 incidents of smoke or fire in 2013 and 85 incidents through the first eight months of last year.