Amtrak temporarily suspended service between Washington D.C. and Richmond, Virginia, after a pair of train cars derailed at Washington’s Union Station.

Emergency responders were evaluating one Amtrak employee, but no other injuries were reported, according to local fire officials. The company said it was investigating the cause of the incident.

The train remained upright inside the tunnel during the incident. All customers from the affected train were redirected to the L’Enfant station of the Virginia Railway Express and were provided alternate transport to Washington Union Station, Amtrak said.

Amtrak initially said that trains running between Washington D.C. and Alexandria, Virginia, would be temporarily disrupted due to “a disabled train in the tunnel blocking the tracks.”

(Updates with Amtrak statement starting in first paragraph)