Amtrak (search) service between Washington and New York was disrupted today by a derailment north of Union Station (search), a railroad statement said.

No serious injuries were reported when two cars of a seven-car northbound train derailed shortly after 9 a.m., spokeswoman Marcie Golgoski said. Neither car overturned, but the wheels did go off the tracks, she added.

Northbound traffic from Union Station has been halted because of the accident. The railroad said it could not estimate how long repairs would take. No cause has been listed for the mishap.