Metro's Orange and Blue lines, and portions of the Yellow, will face 24-minute waits between trains this weekend.
No stations will be closed, and only one (Greenbelt) will be affected by single-tracking.
On the Red Line, trains will run every 10 minutes in two segments: between Shady Grove and Farragut North, and between Glenmont and Judiciary Square during the day (9 a.m.-6 p.m.). Trains will run every 20 minutes otherwise.
On the Green Line, trains will be single-tracking at Greenbelt. Metro says to expect travel times up to 15 minutes longer than usual if you're traveling to or from that station.
Green Line riders transferring to the eastern portion of the Red Line should do so at Fort Totten to avoid delays, Metro said.
On the Orange and Blue lines, trains will run every 24 minutes.
On the Yellow Line, trains will run every 24 minutes. Those traveling north of Mt. Vernon are advised to use the Green Line to avoid Yellow Line delays.
Metro recommends consulting its trip planner to make sure your wait time is as small as possible.
Work will begin 10 p.m. Friday and remain in effect until closing on Sunday.