VIA THE WASHINGTON POST:
Metro riders on the Green, Yellow and Blue lines should expect delays Wednesday because of problems on the tracks.
Trains on the Blue and Yellow lines between National Airport and Crystal City stations are moving more slowly than usual following two derailments of a piece of track equipment.
The machine, called a speed swing vehicle, caused some minor damage to the tracks the first time it derailed. Trains had to share a single track until about 7 a.m. while repairs were made.
The speed swing vehicle was returning to the Alexandria rail yard after being used for overnight work. It was moved to an auxiliary track where it will be stored and examined. Metro plans to move it to the rail yard late tonight, without affecting service.
Meanwhile, on the Green line, trains will run at just 15 mph between the Naylor Road and Southern Avenue stations because of a cracked rail. Temporary repairs have been made, and permanent repairs will be made at night when the rail system is closed.
Metro discovered the cracked rail about 7:28 a.m. on the inbound track.