Commuters at the Smithsonian Metro station were startled by loud noise and smoke Thursday afternoon.
A Metro spokesperson told News4 the incident was caused by a cover to the third rail coming loose and making contact with the rail itself.
Some witnesses said the station filled up with smoke and caused a bit of panic. Metro said the situation is under control and maintenance crews are on the scene to make repairs.
Metro spokesman Dan Stessel says it happened around 2:42 p.m. It wasn't clear why the cover came into contact with the rail.
No one was injured.
The station is open, although the incident caused some delays. Trains briefly single-tracked through the station.
Metro said at 3:50 p.m. that single-tracking had ended, but residual delays remained.