One person died and 80 were injured after an electrical malfunction on the DC metro subway station on Monday.
The incident is still a mystery.
Investigators are still not clear what caused the electrical malfunction.
WBAL TV reported:
The transit network in the nation’s capital remained hobbled Tuesday morning following an electrical malfunction that filled a busy subway station with smoke, killing one woman and sending dozens of people to hospitals.
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The National Transportation Safety Board was investigating the incident, which happened at the beginning of the Monday afternoon rush hour and 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 late Monday night that an electrical “arcing” involving the high-voltage third rail led a train to stop in a tunnel, and it 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, Flanigon said the cause of the arcing was not yet known.
“The third rail is high-voltage direct current, and if that current starts arcing to another conductor that it is not designed to connect with, you get a flash,” Flanigon said. “In certain cases, that arc can start sort of feeding on itself, and it actually generates gases that are more conductive.”