Baltimore’s lone Metro line won’t run this weekend, the Maryland Transit Administration announced, and will reopen Monday with adjusted hours as the agency tests the system’s new railcars.

The MTA will pause service starting at 8 p.m. Friday and resume at 5 a.m. Monday with a slightly modified schedule — the system will close an hour earlier than usual every day.

During the week, the last eastbound train will depart Owings Mills for downtown at 10:57 p.m., and the last westbound train will depart Johns Hopkins Hospital at 11:18 p.m. On weekends and holidays, the last eastbound train will leave at 11:05 p.m. and the last westbound train will leave at 11:15 p.m. Service will continue to start at 5 a.m. on weekdays and 6 a.m. on weekends.

The agency anticipates restoring regular hours by Oct. 1 and will make the necessary service adjustments for special events like Orioles games and Preakness.

The closure and adjusted hours will allow the agency to continue testing the first of the brand-new railcars that many hope will help restore the beleaguered system.

The 78 new train cars are the first major investment in the heavy rail line in decades. The system has used its original fleet of 100 railcars, some of which are no longer operational, since service opened in 1983.

The fleet’s age is the root of many of the technical challenges that cause train delays and impact the system’s reliability, officials have said. Ridership has lagged over the years as commuting habits have changed, driven not only by operational struggles but issues with cleanliness, passengers using drugs onboard and other rider experience concerns.

The more than $500 million mix of state and federal funds that purchased the new railcars also covers a new train control system needed to run them. The MTA has closed the Metro for weekend testing several times since last fall, and will use the extra hour of daily non-service time to ramp up testing ahead of the first new trains entering service later this year.