The Massachusetts Bay Transportation Authority (MBTA) board approved a $54 million plan to bring battery-electric train service to the Fairmount Commuter Rail Line, which will ultimately result in more frequent service and lower emissions in surrounding communities.

Keolis Commuter Services, the operating partner for the MBTA Commuter Rail, submitted an innovation proposal to the MBTA in December 2023 with a plan to introduce battery-electric multiple unit trains (BEMUs) onto the Fairmount Commuter Rail Line.

The Importance of New Trains

The trains will provide faster, quieter, and more reliable service with notably less air pollution in the environmental justice corridor served by the Fairmount Line.

With approval from the MBTA board, the MBTA and Keolis can now finalize the details of the contract, including a timeline for service to begin.

It is anticipated trains would run every 20 minutes on weekdays. Subject to the procurement process, the first train is expected to enter service on the Fairmount Line in early 2028.

“There have been discussions about electrifying our rail network for many years. This agreement is a gamechanger that will benefit generations of passengers, beginning first on the Fairmount Line,” said MBTA GM/CEO Phillip Eng. “By embracing new technologies, we will be able to electrify the Fairmount Line sooner within our existing available funding. Understanding the billions of dollars needed to fully electrify our entire system, this is the first step that I believe will pave the way to a profound transformation that can bring the future of our rail network that much closer.”

How BEMUs Work

BEMU trains use hybrid power with an onboard battery that charges when overhead catenary wires are available, such as at South Station. The trains can then run on battery power.

Because they are electric, these trains emit less air pollution and reduce energy consumption. BEMU trains also provide passengers with smoother rides, more space, and a modernized commuting experience.

Additionally, BEMUs operate a quieter service, significantly reducing noise and vibration for passengers and residents adjacent to the route, yards, and maintenance facility.

The agreement follows a due diligence posting in March 2024 after the MBTA received Keolis’s proposal.

With this agreement in place, Keolis will act as a Project Delivery Partner (PDP) to manage the new decarbonized fleet, additional power and charging infrastructure, and a new light maintenance facility.

The PDP approach is split into two phases, beginning first with the preparation phase to design and develop procurement documents and following with the delivery phase to project manage and integrate the BEMU fleet.

The Fairmount Commuter Rail Line is the shortest of the Commuter Rail Lines with nine stations (including South Station and Readville). As of April 2024, the line carries approximately 3,200 passengers per day.

Battery-electric service will save 1.6 million gallons of fuel and mitigate 17,700 tons of carbon dioxide per year compared to diesel.