The Marine Corps Marathon will adjust start times, racecourses and provide shuttle service for runners and spectators to accommodate the lack of Metrorail service in the hours before the start of the two races.

WASHINGTON — The Marine Corps Marathon will provide an extended start window, alter racecourses and offer shuttle service for runners and spectators to accommodate the lack of Metrorail service in the hours before the races begin, organizers said Wednesday.

As part of Metro’s ongoing rebuilding program, Metro officials have said they would not open early for special events including the marathon. In years past, an average 24,000 runners and spectators have taken advantage of the early transit service for the annual event.

“This change in the timeline has prompted a series of adjustments to both the Marine Corps Marathon and the MCM 10K to meet the primary goal of affording each of the 30,000 runners a fair chance to beat the (14th Street Bridge) by 1:15 p.m. and soon after cross the finish line at the Marine Corps War Memorial,” said Marc Goldman, marking director for the marathon.

The marathon will start as previously scheduled with the wheelchair racers at 7:40 and runners at 7:55 a.m. But all runners have a full hour — until 8:55 a.m. — to begin the 26.2-mile course. The extended start window is intended to accommodate runners who experience transportation delays the morning of the race on Oct. 30, Goldman said.

The companion 10-kilometer race will begin at 9:15 a.m. But the entire course will remain in Arlington County and will no longer begin on the National Mall. Several segments of the marathon course have also been changed, adding more segments in Arlington County and shortening the route along the Rock Creek Parkway.

Runners will now cross the 14th Street Bridge earlier at mile 18 instead of mile 20 in order to help runners cross the bridge before it reopens and the course closes, Goldman said.

Once Metro opens at 7 a.m., eight-car trains will run with increased frequency on the Blue and Yellow lines to serve race participants. However runners are encouraged to find other transportation options, he said.

To help them, the race has organized shuttle service to the runners village. And free parking will be available at 23rd Street and Crystal Drive in Crystal City.

Shuttles for runners begin as early 4:30 a.m. Spectator shuttles begin at 5 a.m.

Shuttle service for runners:

Crystal City free parking 4:30 to 8 a.m.

Gaylord National Resort at National Harbor from 4:30 a.m. to 6:45 a.m.

Ronald Reagan Building and International Trade Center 4:30 to 7 a.m. (return via Metro to Federal Triangle)

Shuttle service for spectators or runners:

Ballston Commons Mall 5 to 9 a.m. via ART 42 bus (return via Metro to Ballston)

Gaylor National Resort at National Harbor to Eisenhower Metro 6:45 a.m. Return service through 5 p.m.

Paid parking will be available:

Ballston Commons Mall

Ronald Reagan Building and International Trade Center

Gaylord National Resort at National Harbor

Pentagon City Mall

See the new course maps here: