I had nothing to do with this:
It was a commuter’s worst nightmare: a Metro train abruptly stops, goes dark and fills with smoke in a tunnel in downtown Washington. Before it was over, one woman was killed and more than 80 passengers were suffering from respiratory problems and other health issues.
[A]uthorities now believe they know why the train, which had just left the L’Enfant Plaza station, came to a halt about 800 feet into the tunnel. The National Transportation Safety Board said “an electrical arcing event” occurred about 1,100 feet in front of the train. The event filled the tunnel with smoke, the NTSB said.
The agency said the arcing involved cables that power the third rail. Arcing is often connected with short circuits and may generate smoke. There did not appear to have been a fire.
Train service has been mostly restored, except for Yellow and Blue line service to L'Enfant Plaza.