Red, Orange and Green line riders will have trackwork to contend with this weekend, Feb. 22-24. The work is part of Metro's ongoing efforts to rebuild its system.

Here's what to expect:

• On the Orange Line, shuttles will replace Vienna and Ballston as workers prepare for the arrival of the new Silver Line. Four stations -- Vienna, Dunn Loring, West Falls Church and East Falls Church -- will be closed. Both express shuttles and local shuttles, which stop at every stop, will be available. Plan to add between 25 to 50 minutes of travel time if using the shuttles.

• On the Red Line, trains will single-track in two different sections: between Friendship Heights and Van Ness, and between Takoma and Rhode Island Avenue. Trains will operate about 24 minutes apart between Shady Grove and Glenmont, except for Saturday and Sunday between 9 a.m. and 9 p.m. between Van Ness and NoMa-Gallaudet, when trains will run about 12 minutes apart.

• On the Green Line, trains will single-track between Greenbelt and College Park.