Starting next week, riders no longer will encounter scheduled delays starting at 8 o’clock on weeknights, General Manager Richard Sarles said. (Susan Biddle/For The Washington Post)

Metro is going to narrow the window for weeknight work on the tracks, General Manager Richard Sarles said Wednesday.

The late-night maintenance program had been starting at 8 p.m. on some lines. As of next week, it will be scheduled to begin at 10 p.m. on Mondays through Thursdays, two hours before Metrorail closes.

That means Metrorail riders will face fewer hours traveling through work zones where trains must share tracks. The track-sharing generally adds about 10 minutes to a rider’s travel time as the trains take turns passing through the work zones.

This week, for example, trains are sharing tracks on sections of the Red and Blue lines starting at 8 p.m.

Speaking with reporters and editors at The Post, Sarles said the intensive phase of Metrorail rebuilding that riders have seen for the past two years will continue through 2017, at which point the system should have achieved a “steady state of good maintenance.”

Under Sarles, the transit authority’s strategy for the past two years has been to focus much of the rebuilding effort on weekends, when fewer people ride. Metrorail recently updated its schedule for major weekend track work — the kind that shuts down stations — through the end of 2013.

The workweek has not escaped completely, however. Metro did end an earlier program of midday track work, but the late-night program continues, even though the program has progressed to the point where the reduction in hours is now possible, Sarles said.

Pushing the start time for all late-night projects from 8 p.m. to 10 p.m. should be a welcome change for many late workers, as well as for restaurant patrons and movie-goers. Fans attending a three-hour night game at Nationals Park will still encounter the 10 p.m. delays on their way home.