By Shangcao Yuan, Special to the Reporter
A long-awaited plan to bring battery-powered trains and more frequent service to the Fairmount Line has been pushed back after MBTA officials required accessibility design changes.
The first of the battery-electric multiple-unit trains, known as BEMUs, is now expected to arrive for testing in 2029, and service is expected to begin in 2030.
The delay has raised questions among advocates and elected officials along the Fairmount corridor. Residents in Dorchester, Mattapan, Hyde Park, Readville and other communities have spent years pushing to replace diesel-powered commuter rail trains with cleaner, more frequent service.
The Reporter requested an interview with MBTA officials, but the agency repeatedly directed the newspaper to the recording of the May 28 and June 11 MBTA Board of Directors meeting, where the delay was discussed, and its presentation of the plan.
Michael Muller, the MBTA’s executive director of commuter rail, told board members that the agency’s original projection was to have the vehicles delivered for revenue service in 2028. The company chosen to build the trains – Stadler US Inc. – offered a design that could have met that timeline, but it used a lower accessibility standard than the MBTA wanted for the Fairmount Line, Muller said.
Federal accessibility rules require accessible seating in only one car per train for rapid rail, Muller told the board, while they require accessible seating in every passenger coach for commuter rail—the level of access Fairmount Line riders have today.
Because the proposed BEMUs resemble rapid-transit vehicles but would operate on the commuter rail system, Muller said MBTA officials required a design change to include accessible seating in all three passenger cars of each four-unit train, which includes a battery unit.
“We’re moving forward on technology, moving forward on decarbonization, moving forward on service frequency; we’re not going backwards on accessibility,” Muller said during the meeting.
Muller said MBTA officials considered other options but concluded the current procurement remained the fastest path to cleaner Fairmount Line service.
“We determined that there was not an alternative that actually delivers decarbonized service on the Fairmount Line sooner,” Muller said.
The revised timeline calls for awarding the Fairmount Line BEMU contract in 2026, delivering a demonstration mockup in 2028, and testing the first train in 2029, with 2030 expected to be the first full year of BEMU service.
The proposed BEMUs would be four-unit, two-level trains able to operate on onboard battery power or overhead catenary, with service every 20 minutes and the future possibility of 15-minute service on the Fairmount Line. The MBTA says the trains would reduce noise and vibration for passengers and residents near the tracks, yards and maintenance facilities.
According to the MBTA presentation, the BEMUs would reduce diesel use by 1.6 million gallons and cut carbon dioxide emissions by 17,700 tons per year compared with diesel service—roughly the annual emissions of about 3,500 passenger vehicles.
The project has been closely watched since Governor Maura Healey and other officials visited Mattapan in 2024 to celebrate MBTA board approval of the battery-electric plan. In a March 2025 Reporter story, advocates said they viewed the project as a transit equity victory for communities long affected by diesel emissions and limited transit options.
The supporting infrastructure for the project is estimated to cost $68 million to $84 million. The work includes a maintenance facility at Readville Yard, charging points, a substation, clearance work at South Station, project administration, and already completed track renewal.
State Representative Russell Holmes, who has long advocated for Fairmount Line improvements, said he was surprised to learn about the updated timeline from a reporter rather than the MBTA or Keolis Commuter Services, the private operator of the MBTA Commuter Rail network.
“I don’t like getting surprised when it’s The Reporter calling me instead of the MBTA or Keolis,” Holmes said.
Holmes said he did not receive the presentation from the MBTA until June 8, 11 days after the board meeting.
Holmes said the project’s inclusion in the MBTA’s capital investment plan gives him confidence it is still moving forward, but he added that delays erode public trust among residents who have heard previous promises about the line.
Rep. Russell Holmes
“We’re trying to show people that we can deliver what we say we’re going to deliver so we can get these people out of their cars,” Holmes said. “It’s just another one of those disappointments of not delivering the public transit that folks have come to demand and expect.”
Holmes said his commitment to electric trains and reliable service remains “unwavering.”
“We have to stay true to our word and deliver on exactly what we said we want to do,” Holmes said.
MBTA board members also criticized the agency’s outreach. Director Mary Skelton Roberts said advocates who had pushed for the line for decades should not have had to learn about the delay at a board meeting.
“The headline is you’ve got to be engaging with the community,” Skelton Roberts said. “It’s just not fair for them to hear this at the board meeting.”
Director Chanda Smart also called the lack of outreach “unacceptable,” saying advocacy groups that regularly attend board meetings should not have been “blindsided.”
Caitlin Allen-Connelly, executive director of TransitMatters, a statewide advocacy group focused on improving public transportation, climate and mobility access, described the delay as “a complex and challenging trade-off.”
She said the updated timeline is frustrating for communities along the Fairmount corridor because it means residents in Dorchester and Mattapan face more years of diesel emissions and less frequent service. But she also said the accessibility change was necessary.
“Accepting the original timeline would have locked us into an inequitable 30-year mistake for riders with disabilities,” Allen-Connelly said.
Still, she said the delay raises questions for the MBTA: why those accessibility requirements were not included in the procurement from the beginning. She said the MBTA should explain the delay directly to riders at stations and in communities along the corridor.
“It’s not just about posting a presentation online,” Allen-Connelly said.
This story is part of a partnership between the Dorchester Reporter and the Boston University Department of Journalism.
