WASHINGTON (AP) — Metro says buses will replace trains on parts of the blue and red lines this weekend.

Metro says two red line stations, Medical Center and Bethesda, will be closed. Free shuttle buses will take passengers between the Friendship Heights and Grosvenor-Strathmore stations. On the blue line, buses will replace trains between Franconia-Springfield and Van Dorn Street. Metro says customers traveling through the two work zones should add 30 minutes to their travel time.

In addition, trains will share a single track on portions of the orange and green lines, leading to delays. Orange line trains will single track between East Falls Church and West Falls Church and between Stadium-Armory and Cheverly. On the green line, trains will single track between Fort Totten and Prince George’s Plaza.

(Copyright 2012 by The Associated Press. All Rights Reserved.)