Updated at 9:34 a.m.

Riders on Metro’s Green and Yellow lines should expect delays of up to 20 minutes in both directions. Service problems, Metro said, over the last hour are the cause of the delays. It is not immediately clear how long the delays will last.

Updated at 8:32 a.m.

Trains are no longer sharing a track on the  Green and Yellow lines.

Original post at 8:23 a.m.

Riders on Metro’s Yellow and Green line trains should expect delays Monday morning.

The trains are sharing a track between the Mount Vernon Square and U Street stations. There is a broken train at the Shaw stop. It is not clear how long the delays will last.