From WMATA:
“On Saturday, Sept. 27 and Sunday, Sept. 28, free shuttle buses will replace trains between Foggy Bottom and Pentagon on the Blue Line and Foggy Bottom and Court House on the Orange and Silver lines.
There will be no Blue Line train service at Pentagon, Pentagon City, and Crystal City, however Yellow Line service will be available. Crews will be working to replace fasteners and anchors as well as performing maintenance on the third rail and rail renewal to ensure reliability.
Additional weekend track work
Crews will perform track work on the Orange and Silver lines each of the next three weekends, resulting in single-tracking:
∙ Sept. 6-7: Orange Line will single track between Cheverly and New Carrollton. There will be no Silver Line service to New Carrollton.
∙ Sept. 13-14: Orange and Silver lines will single track between Ballston and East Falls Church.
∙ Sept. 20-21: Orange Line will single track between Cheverly and New Carrollton. There will be no Silver Line service to New Carrollton.”