Representatives of the Massachusetts Bay Transportation Authority (MBTA) recently joined with Massachusetts Governor Maura Healey, other state officials, and various stakeholders to sign a $54 million plan to introduce battery-powered electric train service on the Fairmount Commuter Rail Line.

In July, the MBTA board approved a plan by Keolis to introduce battery-powered multiple unit trains (BEMUs) on the Fairmount Line. Depending on the procurement process, the first train is expected to enter service in early 2028. The trains would run every 20 minutes on weekdays.

BEMU trains use hybrid propulsion and have an on-board battery that is charged when overhead lines are available, such as at South Station. The trains can then run on battery power.

“The Fairmount Line – from South Station through Dorchester and Mattapan to Hyde Park – will be the first commuter rail line in Massachusetts to offer 100 percent electric train service,” Healey said in a press release.

The Fairmount Line is the MBTA’s shortest commuter rail line, with nine stations. The line is used by about 3,200 passengers daily. Battery-electric operation saves 1.6 million gallons of fuel and 17,700 tons of carbon dioxide per year compared to diesel trains, MBTA officials said.

“Knowing that billions of dollars are needed to fully electrify our entire system, we are proud to have found a way to electrify this corridor more quickly within available resources,” said MBTA General Manager Phillip Eng. “This work will help us improve and decarbonize our service across our entire regional rail network.”

Meanwhile, the MBTA has signed an option to replace an aging fleet of rail cars in its regional system under an agreement with Hyundai Rotem. The agreement adds 41 double-deck commuter trains to a previous order of 83 cars. The procurement contract with Hyundai Rotem is valued at $305 million.

The new cars feature more seating for up to 179 passengers per car, designated areas for passengers with disabilities, real-time information systems with automated announcements and message displays, and improved accessible restrooms with touchless faucets.

“As we continue to see a strong return in commuter rail ridership, investing in our fleet will not only improve service levels but also provide the public with a more comfortable and reliable experience,” said Eng.

The MBTA has received 76 new double-deck cars, 64 of which are already in service. The remaining cars are currently undergoing final testing and are expected to enter service in late 2024.