A track vehicle derailment knocked out Yellow Line service into the District on Monday, Sept. 21, forcing riders on the Virginia side of the Potomac to reroute during the morning commute.

The Washington Metropolitan Area Transit Authority (WMATA) said the vehicle derailed during scheduled weekend bridge and track work on the Yellow Line. It was a maintenance vehicle, not a passenger train. No injuries were reported, according to WMATA spokesperson Jordan Pascale's office.

Yellow Line trains ran only between Huntington and Arlington Cemetery through Monday afternoon, according to a WMATA service alert posted at 11:25 p.m. Sunday, Sept. 20. Riders heading into D.C. were told to switch to Blue Line trains or board shuttle buses running between the Pentagon at Bus Bay L7 and L'Enfant Plaza at 7th Street and Maryland Avenue SW.

The disruption affected riders at five Virginia stations. Trains from Huntington, Eisenhower Avenue, King Street-Old Town, Braddock Road and Potomac Yard could not cross the river on their usual route, The Alexandria Brief reported.

Crews worked through the night to address the derailment and finish the bridge and track rehabilitation, WMATA said. By Monday morning, the agency said crews had made significant progress overnight and expected track repairs to wrap up after morning rush hour. WMATA had not posted a confirmation of full service restoration as of Monday evening.

Some riders said the transit agency's communication fell short. One commuter posted on X that platform messaging at Gallery Place was confusing.

@Silkloomer: "The messaging for Yellow line on the platforms at Gallery Place station this morning was so confusing and the important information that trains were not running in the direction of Huntington was conveniently left out. Go figure."

The Yellow Line had already been shut down Sunday, Sept. 20, and Sunday for what WMATA described as work to improve rail infrastructure reliability, safety and operational performance, according to DC News Now. The derailment happened during that maintenance window, and the cause has not been made public.

Additional service changes are scheduled. WMATA plans to suspend Yellow Line service again the weekend of Sept. 26 and Sept. 27 for the same rehabilitation work. On Wednesday, Sept. 23, Yellow and Blue line trains will single-track between Reagan National Airport and Pentagon City from 9:30 a.m. to 3 p.m.

Riders can check Metro Pulse for real-time service updates.