Thousands of students, joined by their families and friends, will pack into Comcast Center on Sunday for the University of Maryland’s spring commencement. But anyone planning on taking Metro to College Park should prepare for a long trip.

As part of the transit agency’s rebuilding efforts, Metro plans to close the College Park station this weekend, along with the Greenbelt and Prince George’s Plaza stops.

Free shuttle buses will replace Green Line trains along the affected stretch. Metro warns riders that those using the buses should add 35 minutes to their trip.

“Metro and the university should have been a little bit more aware,” said Tina Slater, president of the Action Committee for Transit, a local transportation advocacy group. “With something as huge as a graduation of thousands of students with that many more thousands of relatives and friends coming to town, that’s a really bad time to be working on that end of the Green Line.”

Weekend track work and station closures have become a routine headache across the region. As part of a $5 billion effort to repair its aging rail system, Metro has made weekend station shutdowns a regular occurrence for more than two years.

Slater said she understands that ridership is lower on weekends, making it an ideal time for work, but thinks that Metro should keep a closer eye on major events when planning for station closures.

Dan Stessel, a Metro spokesman, said the weekend Green Line work is “critical” to the reliability and safety of the transit system. He added that it’s difficult to find a weekend when there isn’t some big event happening in the area.

“If we rescheduled rebuilding work every time there’s a major event, we’d never get any rebuilding done,” he said. “There are major events every weekend. But this work has to get done, and weekends are when it happens.”

The transit agency announced the track work in January and didn’t hear from the university until Tuesday, he said. A university representative contacted Metro to find out about the agency’s service plan but did not ask for the work to be rescheduled, according to Stessel.

Beth Cavanaugh, a university spokeswoman, said the school just learned about the closure. She added that the school contacted Metro but offered no details. The school will hand out more than 7,600 degrees Sunday.

The Green Line stations are closing for track maintenance and ongoing construction of a test track to be used by Metro’s new 7000 series rail cars. The new cars are expected to arrive later this year.

This isn’t the first time Metro work has coincided with U-Md.’s commencement. Green Line trains single-tracked along the same stretch during commencement weekend in 2012.

Metro reports that 1,852 riders entered or exited the College Park stop that Sunday. That was up from the 1,257 riders the previous Sunday.

Stessel said the agency will have additional employees available to help riders get to or from College Park.