Trains on the blue, orange and silver lines are delayed by 20 to 40 minutes, and the delays will continue through Tuesday night, according to a WMATA release.

Defective rail fasteners near the Smithsonian Metro station are causing single tracking for the orange and blue line trains between the Smithsonian and Federal Center stations, according to the release.

“Customers on these lines may experience significantly longer waits and crowding on platforms and trains,” according to the release.

Silver line trains will run only between Ballston and Wiehle-Reston East to reduce congestion, according to the release. WMATA officials encourage commuters to use Metrobus 38B as an alternative to the orange line between D.C. and Arlington stations, and to use the yellow line instead of the blue when traveling to stations in Virginia south of the Pentagon.

WMATA will extend single tracking to the McPherson Square station after rush hour to repair rail ties.