Green Line service on the B, C and D branches through Brookline shuts down for nine days starting Saturday, Sept. 26. The MBTA will suspend trains for signal upgrades through Sunday, Oct. 4.

On the B Branch, service stops between Government Center and Babcock Street. On the C Branch, the closure stretches from Government Center to Kenmore. The D Branch will be suspended between North Station and Kenmore.

The MBTA said the shutdown will allow crews to replace the Green Line's century-old signal system with modern equipment in the central tunnel, according to the agency's Sept. 18 press release. The new signals will be compatible with the upcoming Type 10 Green Line cars.

Shuttle buses and free alternatives

Free shuttle buses will replace train service on all three Brookline branches. B Branch shuttles run between Babcock Street and Back Bay. C and D Branch shuttles run between Kenmore and Back Bay. At Back Bay, riders can transfer to the Orange Line for continued service downtown toward North Station.

For a trip from Boston College to Park Street, the MBTA said riders should add at least 25 extra minutes beyond their normal commute.

Two other free options are available. Route 57 bus service, which runs parallel to the B Branch between Kenmore and Packard's Corner, will be fare-free. The Framingham/Worcester Commuter Rail line will also be free between South Station and Lansdowne for the duration of the closure. Fares at Kenmore will be waived, with gates open, and all surface-level stops west of Kenmore will also be free.

Accessible van service will be available for stops between Kenmore and North Station. Transit ambassadors and MBTA staff will be on-site to help riders navigate the changes. Riders can check updated routes and travel times at mbta.com/PlannedWork or subscribe to T-Alerts for service updates.

Second shutdown in two months

The Sept. 26 closure is the second nine-day Green Line shutdown this year. A similar closure in August suspended service on portions of all four branches for the same signal work, as Patch reported.

The pattern is not over. Another round of suspensions covering the same branch segments is scheduled for the weekend of Oct. 31 through Nov. 1.

Through August 2026, the MBTA had already shut down portions of the Green Line for 78 days, roughly one-third of the year, according to data compiled by the advocacy group TransitMatters and reported by the Boston Globe. Only 15 percent of the cabling for the new signal equipment had been installed as of early September, the Globe reported. The MBTA's overall infrastructure backlog is estimated at $25 billion.

"We're doing this work instead of kicking the can down the road," MBTA Chief Operating Officer Ryan Coholan told the Globe in a Sept. 1 article about the broader shutdown pattern.

Spokesperson Lisa Battiston told the Globe that more outages will "likely" follow in 2027 to prepare for new train cars.

C Branch note for Brookline riders

During the closure, C Branch trains will also bypass Brandon Hall station through Oct. 4 as part of a separate accessibility improvement project along Beacon Street in Brookline. The MBTA said additional C Branch accessibility work at several street-level stops will advance in October.

The next scheduled Green Line suspension runs Oct. 31 through Nov. 1.