Above, workers are shown along the right-of-way during a Red Line diversion in 2025. MBTA photo
Dorchester and Mattapan transit riders will face significant service disruptions in May as the MBTA carries out another round of signal upgrades and infrastructure work along the Red Line and Mattapan trolleyway.
The planned outages will hit the Ashmont branch particularly hard and, at times, overlap with a full shutdown of the Mattapan High-Speed Line.
The most substantial disruption is scheduled from the evening of May 14 through May 18, when Red Line service between Broadway and Ashmont will be suspended. Shuttle buses will replace trains along the route, requiring riders to transfer at Broadway or JFK/UMass.
MBTA officials say riders traveling from Ashmont to downtown Boston should expect an additional 30 to 40 minutes of travel time.
The shutdown affects Dorchester neighborhoods along the Ashmont line, including Savin Hill, Fields Corner, Shawmut, and Ashmont.
According to the MBTA, the work is part of final testing and commissioning of a new digital signal system designed to improve reliability and service frequency on the Red Line.
The Mattapan Line will also be suspended from the evening of May 14 through May 16, with shuttle buses replacing trolley service between Ashmont and Mattapan. The timing of that closure overlaps with the Red Line shutdown.
The MBTA is encouraging riders to consider the Fairmount commuter rail line as an alternative during the outage.
Further Red Line service suspensions are scheduled for May 29 through May 31, when both the Ashmont and Braintree branches south of Broadway will again be replaced by shuttle buses.
Earlier in the month, Red Line service between Broadway and Quincy Center will also be suspended from May 2 through May 4, primarily affecting the Braintree branch.
Riders are advised to allow extra travel time, monitor MBTA alerts, and plan alternate routes where possible. The agency says the work is part of ongoing efforts to modernize aging infrastructure and improve long-term service reliability across the system.
–REPORTER STAFF
