The Fairmount commuter rail line will be free during the 16-day shutdown of the Ashmont and Mattapan branches of the Red Line, MBTA officials said Wednesday.

A similar policy was in place during last year’s Orange Line shutdown, and Mayor Wu noted it boosted ridership. She pushed for it to be reintroduced for the Fairmount Line, which runs through Dorchester and Mattapan, but MBTA officials were initially reluctant.

The Fairmount line runs between South Station and Readville, with stops on Blue Hill Avenue, Morton Street, Talbot Avenue, as well as in Four Corners/Geneva, Uphams Corner, and Newmarket.

Free shuttle buses will also be available to MBTA customers during the shutdown.

The Red Line’s shutdown is set to start on Saturday, Oct. 14 and end Sunday, Oct. 29. T officials say the shutdown is needed for track work that would otherwise take six months of weekend and evening work. The agency is also seeking to make repairs to Savin Hill Station and JFK/UMass Station, a major transit hub in need of an upgrade.

The MBTA has seen systemwide slowdowns, driven by safety concerns at the federal level. Commuters on the Red Line in particular have seen trains slow to a crawl, and wait times that used to be six minutes are now up to 15 to 20 minutes.

“The upcoming work on the Ashmont Branch and Mattapan Line is critical to addressing and improving safety and reliability along this stretch of the Red Line, and the complete closure of these lines allows us to accomplish vital work in 16 days,” MBTA GM Phillip Eng said in a statement on Wednesday. “While this service change will be challenging for our riders, they have let me know that they appreciate that we are committed to improving their travels.”

The MBTA has a public meeting planned on the Red Line closure, set for tonight at 6 p.m. on Zoom.

This post was updated to note riders do not need to flash their CharlieCards to board the free Fairmount Line. The MBTA originally said they needed to do so before issuing a correction Wednesday afternoon.