Metro riders should factor an extra 20 to 30 minutes into their commute this weekend while the rail system shuts down some trains for track work.

Starting 10 p.m. Friday, shuttle buses will run in place of Orange Line trains from Court House to Foggy Bottom, as well as along the Blue Line between Pentagon and Foggy Bottom, according to a Metro release. The shutdown will “allow for rail fastener renewal, insulator replacement and sludge removal from the tunnel beneath the Potomac River.”

The Rosslyn and Arlington Cemetery stations will close for the weekend, but free shuttle buses will run between Court House, Rosslyn, and Foggy Bottom, and also between Pentagon, Arlington Cemetery, Rosslyn and Foggy Bottom. Blue Line trains will be split to run from Franconia-Springfield and Mt. Vernon Square, cutting through the Yellow Line, and between Foggy Bottom and Largo Town Center.

Orange Line trains will also be divided to run from Vienna to Court House at 20-minute intervals, and between Foggy Bottom and New Carrollton at the normal weekend service levels.

The track work is part of a six-year capital improvement program worth $5 billion to rehabilitate the rail system.