MBTA battery train Fairmount Line cost hits 765.4 million dollars in a 15 year lease for 28 rail cars approved in June 2026

The MBTA battery train Fairmount Line cost reaches 765.4 million dollars

The MBTA battery train Fairmount Line cost is now 765.4 million dollars over 15 years, after the Massachusetts Bay Transportation Authority board voted in June 2026 to lease 28 battery electric rail cars for the Fairmount Line, the commuter rail route connecting Readville and South Station in Boston. The cars are built as 7 four car trainsets called battery electric multiple units, or BEMUs, which charge from an onboard battery instead of drawing power from overhead wire for the whole trip. Under the deal, Stadler US Inc, a Swiss rail manufacturer, builds the trains. Rock Rail, a rail financing company, buys them and leases them to Keolis Commuter Services, the contractor that already runs every MBTA commuter rail line, and Keolis will operate the battery trains on the Fairmount Line for the transit agency. Wikipedia lists the route at 9.2 miles.

Battery electric trains and the infrastructure supporting them will deliver a quieter, cleaner, and more reliable ride for our passengers.

Phillip Eng, interim secretary of transportation and MBTA general manager. Source 2.

How the 765.4 million dollar lease breaks down

The 765.4 million dollar total authorized in June 2026 splits into 3 parts, according to the MBTA own board presentation. Leasing the trains themselves costs 574.2 million dollars over the 15 years. Technical support, mobilization, and light maintenance costs 129.2 million dollars. Heavy maintenance, including replacing the traction batteries, the batteries that store the power that moves the train, costs 62.0 million dollars. The total already carries a 5% contingency margin, extra money set aside in case costs run higher than planned, and the authorized first year cost is 30.6 million dollars, plus indexation, a yearly adjustment tied to inflation.

Why the cost grew since the 2024 estimate

The MBTA board first approved this project in July 2024 for a stated 54 million dollars, a figure that covered only an earlier stage of the deal, not the full 15 year equipment lease the board authorized in June 2026. The board own presentation gives 3 specific reasons the total cost has grown since that earlier estimate, reasons neither news writeup on this story reports. Tariffs on specialized rail components raised the price of parts. New design changes let passengers board at every door at platform level, not just 1 door, which added cost. And the June 2026 figure includes a capital maintenance provision, money set aside for major repairs over the life of the lease, that the earlier estimate left out entirely.

A technology choice with critics inside the MBTA own oversight system

Brian Kane, executive director of the MBTA Advisory Board, a separate legislative oversight body that reviews MBTA spending, is the sharpest critic of the technology itself, not just its price. He argues the MBTA should have strung catenary, the overhead wire that powers a train directly, along the whole line instead of relying on onboard batteries.

But they're locking themselves into this technology by not stringing catenary everywhere, and I just think it's a strategic mistake.

Brian Kane, executive director of the MBTA Advisory Board. Source 3.

A schedule that has already slipped by about 2 years

Keolis crews already finished the groundwork, replacing over 28 miles of rail, nearly 158,000 feet, on the Fairmount Line in a 12 million dollar project completed December 1, 2025. The battery trains themselves are running later than once planned. The MBTA now expects its first test train by the end of 2029 and passenger service in 2030, roughly 2 years behind an earlier 2028 estimate.

We need to hold ourselves to a timetable so that we don't get in the situation we're in now, where it's taken seven years to make even modest progress.

State Senator Brendan Crighton, a Massachusetts state senator. Source 3.