The Orange Line is about to shut down for 11 days. Here’s what to know.

Orange Line service will be suspended between the Oak Grove and Back Bay stations from Aug. 20 to Aug. 30 due to track and signal upgrades, according to the MBTA.

The partial shutdown will be the second major subway service change this month after the Green Line shutdowns from Aug. 8 to Aug. 16. Orange Line riders will have several alternate travel options to choose from during the 11-day shutdown.

Free and accessible shuttle buses will run between Oak Grove and North Station, with express services at Oak Grove, Malden Center, Wellington, and North Station, the MBTA said in a press release. Fare-free Commuter Rail service will also be available between Oak Grove and North Station via the Haverhill Line, which also stops at Malden Center.

Downtown commuters are encouraged to use parallel Green Line service between North Station and Copley, which is less than a quarter-mile from Back Bay. Extra Green Line trains will run during the shutdown to accommodate Orange Line riders, the MBTA said.

During the service suspension, maintenance crews will replace rail fasteners, rails, plates, and insulators between Tufts Medical Center and Haymarket. They will also replace ties, rails, and plates as well as conduct tamping work between Haymarket and the Assembly truck pad, according to the MBTA.

Signal rack relocations will take place at North Station, Community College, and Wellington to permanently install this equipment within signal houses. Final signal completion work will also take place between Oak Grove and Tufts Medical Center, officials said.

Several other side projects will also be completed during the shutdown to take advantage of the easier access along the line. These include platform upgrades, bridge inspections, deep cleans of stations, plumbing and drainage improvements, and radio installations, according to the MBTA.

The transit authority stressed that a multi-day shutdown throughout the week was the most effective option to address these changes rather than overnight work or intermittent weekend shutdowns.

“This work cannot be performed during the overnight hours when the MBTA does not operate, and would be extremely inefficient and costly if planned during single weekend outages,” the MBTA said in the press release. “Closing a section of the transit system for multiple days is the most efficient way to perform the MBTA’s routine maintenance, revitalization efforts, inspections, and upgrade work, and combines the efforts of multiple contractors and the MBTA workforce around the clock 24/7 to maximize productivity.”

Up-to-date service information will be available via T-Alerts, the MBTA’s website, and the transit authority’s X account.