Riders on most lines will be unaffected by the rebuilding program this weekend. (John McDonnell/The Washington Post)

The Orange Line is the only one of Metrorail’s five lines that is scheduled to be disrupted this weekend as part of the transit authority’s long-term rebuilding program. And the Orange Line disruption will be very limited after 9 p.m. Saturday.

Participants in the Marine Corps Marathon will appreciate that, since the big event is scheduled for Sunday morning. Metro will open at 5 a.m. Sunday, two hours earlier than normal. The runners start at 7:55 a.m., but the organizers recommend that runners arrive two hours before start time to get through the security checkpoint and prepare for the event. The start line will be on Route 110, halfway between the Pentagon and Arlington Memorial Drive. The closest Metro access to the start is the Pentagon station on the Blue and Yellow lines. Arlington Cemetery station will be closed until 8:30 a.m. We’ll have more details about the marathon later this week.

And in case you were wondering: This is not the weekend when the clocks fall back an hour. That’s the first weekend in November.

Orange Line
Crews will be working on the track bed and the third rail from 10 p.m. Friday through the midnight closing Sunday. From 9 a.m. to 9 p.m. Saturday, every other train will operate between Vienna and Cheverly only. Riders traveling to or from Landover or New Carrollton at the east end of the line should add about 12 minutes of travel time because of the reduced service in that area, the transit authority said. Before 9 a.m. and after 9 p.m., the trains will operate on their normal weekend scheduled.

Then on Sunday, trains all along the line will operate every 16 minutes, just a minute off their normal Sunday schedule of every 15 minutes.

Robert Thomson is The Washington Post’s “Dr. Gridlock.” He answers travelers’ questions, listens to their complaints and shares their pain on the roads, trains and buses in the Washington region.