The incident occurred between the Cheverly and New Carrollton stations.
Metro riders should expect delays on Blue and Orange lines because of disabled trains.
Delays on Blue and Orange lines because of signal problem. Trains briefly shared a track.
Delays on three of Metro's five rail lines. Unclear how long delays will last on Red, Orange and Blue lines.
Metro clears delays on Green and Orange lines after earlier problems.
It is not the first time Metro has received complaints from commuters train service on weekends that are holidays for some but not others.
Work ran longer than expected but delays were cleared by rush hour.