Earlier, all rail service in that area had been halted, then permitted to run on only a single track. Shuttle buses were provided and many passengers faced long delays.
There were problems Tuesday morning on all five lines of the rail system, but the evening incident seemed to be the most disruptive.
Metro said smoke was reported about 6 p.m. beneath a car of an empty train in the Silver Spring station. The train was empty, apparently because of a problem detected earlier, at Takoma.
As the smoke began to billow, the Silver Spring station was
A woman who was on a train headed toward downtown about 6 p.m. said she saw smoke as she got out of her train at Silver Spring, as she had planned.
Then, “I saw a blast of light and went deaf temporarily,” Nikki Murray said in an e-mail. She said she stood immobile “for half a second, before realizing I should run.” As she ran, she turned and saw a second blast, she said.
She ran down an escalator and out of the station.
A crossing guard in the area said fire leapt high enough on the elevated track to be seen from the sidewalk a block away.
A spokesman for the Montgomery County fire department said that by 6:30 p.m., firefighters had extinguished a fire beneath the train. The fire may have involved a “shoe,” which conducts power from the electrified third rail to the train, said Scott Graham, assistant fire chief. Another possibility, he said, was that the fire involved an insulator.
The fire remains under investigation, Metro officials said Tuesday evening. The cause was believed to be mechanical, and foul play was not suspected, Metro officials said.
Insulator failures, which generate smoke and sometimes flame, have been implicated in several past service disruptions.
As of 7:30 p.m., Metro began running trains on a single track between the Forest Glen station on the north and Takoma on the south. Although trains ran through the Silver Spring station, it remained closed to all passengers for another half-hour.
At least two people who were in the vicinity of the station reported hearing several explosions or loud bangs that appeared to occur as the smoke began billowing from the station.
However, an initial fire department report indicated that no explosion had occurred. The source of the loud noises could not be immediately identified. Cautious officials brought a dog to search beneath the train.
Numerous witnesses saw the smoke and flames from streets near the station. “I saw smoke, then I saw fire,” one said. Another said smoke had blackened the side of the third car of an eight-car train halted in the station.
With the cause of the fire unknown, travel in the underpass beneath the station was also stopped, adding to the disruption in the neighborhood, where many people transfer to and from buses.
A problem with the train was apparently detected at the Takoma station, one passenger said. First the car behind his was emptied, and then the entire train was evacuated, Erik Hope said. After that, he said, the empty train “sped off” toward Silver Spring.
As crowds swelled in the Silver Spring area, some people said that they could not find shuttle buses. One man said he had searched a half-hour.
“I’m not too happy,” said Dean Smehil, 61. “I’ve walked here. I’ve walked there. . . . It’s a little bit frustrating.”
Mark Berman, Dana Hedgpeth and John Kelly contributed to this report.