Metro will open at 6 a.m. Sunday to accommodate runners in the Navy-Air Force Half Marathon -- but reconstruction projects may delay other riders.
Beginning at 10 p.m. Friday night, Green Line trains will operate every 20 minutes. Orange and Blue Line trains will run every 24 minutes, and Red Line trains every 8 to 15 minutes.
There will be additional daytime Red Line trains between Grosvenor and NoMa-Gallaudet.
Silver Line trains will proceed under the regular weekend schedule, as well as yellow lines between Huntington and Mt. Vernon Sq.
Normal schedules will resume on Monday morning.