Why the MBTA chose battery-electric trains to decarbonize a Boston rail line.

Electric vehicles run on batteries, why not trains? The MBTA approved an innovative financial proposal by Keolis to convert old diesel trains to Stadler's modern, faster, and emission-free units.

Jul 28, 2024

Source: Stadler battery-electric multiple unit (BEMU)

I am a commuter rail fan, preferring to take trains rather than sit in Boston’s tortuous traffic jams. Crawling five mph for hours is not my happy time, even when listening to podcasts and books. For decades, I sat in my car, looking through the windshield at the unending line of car brake lights with the intermittent crazy driver squeeze-weaving between my car and the one in front of me. What a waste of time!

Is Boston traffic that bad? Yes! The INRIX 2023 Global Traffic Scorecard ranks Boston as the eighth most congested city, behind larger cities such as New York, London, Paris, and Mexico City. INRIX notes that this extreme congestion slows commuters, delays freight deliveries, and increases climate-damaging fossil fuel emissions. INRIX estimates that the 2023 congestion costs an average driver $1,543 and the City $2.9 billion.

Unfortunately, riding trains is not attractive enough to win over car riders. As a glaring example, the Boston Globe reported that the Massachusetts’ Secretary of Transportation, an advocate for public transit, “has never been to the commuter rail station.” The station [is] just a five-minute drive from her home, [but she feels] “the train is inconvenient…”

Limited schedules, slow trains, and overcrowding during peak hours are cited as the bane of would-be new train riders. The current diesel-powered trains are inflexible and unable to handle faster, more convenient service.

Worse than an inconvenience, diesel trains emit harmful emissions near homes and apartments along the rail lines. The health risks of pollution are so acute that city mayors along the Environmental Justice corridor are pushing the MBTA to expedite the conversion to zero-emission electric trains.

The MBTA's challenge is to achieve this goal for one of the oldest U.S. transit systems, which has been cobbled together since the 1800s. Today, the rail portion of the “T” has grown to more than 700 track miles, with 14 lines, from Boston into eastern and central Massachusetts and parts of Rhode Island.

How does the MBTA go from today’s transit system to a modern one?

Fits and starts from the legislature and the Governor

Trains, like roads and highways, are public goods that support a community's economic development and growth. Lousy transportation does not attract workers, students, and property developers to make a vibrant, modern, world-class city. Looking over news stories for the past ten years confirms that leaders and the MBTA struggle to fund, operate, and modernize Boston’s rail lines.

The legislature’s drive toward net-zero carbon emissions

The legislature recently passed climate policy laws and is considering Bills decarbonizing the rail system. These laws could force modernizing the rail fleet to meet zero-emission goals. For example:

An Act Creating A Next-Generation Roadmap for Massachusetts Climate Policy. In 2021, the MA legislature passed a law requiring the Commonwealth to reach net-zero emissions by 2050. Under this Bill, the Executive Office of Energy and Environmental Affairs, a state agency, set declining emission limits every five years until 2050. The law applies to buildings and transportation in the Commonwealth.
An Act relative to setting deadlines to electrify the MBTA commuter rail. In 2023, twenty-two Massachusetts senators sponsored a bill, S.2217, to prescriptively require new electric trains beginning under Phase 1 by December 31, 2024, through Phase 4 on December 31, 2035. The proposed bill also mandates service frequency standards to ensure that electric trains enter stations every 5 to 30 minutes, depending on the train line. This Bill is now dead.
An Act upgrading the grid and protecting ratepayers. Senate Bill S.2217 was shortened and moved into a new Section 138 of Senate Bill S.2838. The revised section leaves electrification schedules and requirements up to the MBTA rather than prescriptively mandating schedules and performance. Under the new language, the MBTA must hold public hearings on proposed schedules, budgets, construction permits, utility electric service upgrades, and completion dates. The MBTA must also provide its plan to raise and extend station platforms to speed up the flow of customers into and out of train stops.
House and Senate Conference Committee. At the time of this writing, the House version of the Bill does not include train electrification. The differences between the two bills have been sent to the Conference Committee. [Update for Aug 1, 2024: The House and Senate could not reach a compromise to pass a joint climate Bill. The bill died for the current legislative session and will have to be reissued in the next session, starting in 2025. See “Finger-pointing galore as climate legislation stalls.”]

The MA Governor promised transit reform but ordered another study

Governor Maura Healey campaigned to fix the commuter rail rail service.

However, instead of proposing to fund and fix the MBTA, the Governor issued Executive Order 626, “Creating the Governor's Transportation Funding Task Force,” which seeks a recommendation for capital sources for the MBTA’s repair, expansion, and modernization efforts.

The study’s task force will report findings by December 24, 2024. Hopefully, the task force will recommend model legislation for an electric regional rail system.

The MBTA continued to study electrification options

Despite budget shortfalls in the MBTA’s operating and capital plans, the agency continues to evolve its decarbonization plans with two approaches:

1. All electric: The MBTA Rail Vision plan

In a 117-page report, the MBTA Rail Vision analyzed six transportation alternatives to achieve the best cost for service improvements and return on capital investment.

The best overall return on investment was the full transformation to electrified regional rail by installing an overhead catenary system (OCS).

Electrification technology is built around the electric multiple unit (EMU), which powers each passenger carriage with an electric motor rather than a heavy diesel locomotive pulling a long line of carriages. EMUs are more flexible than diesel trains, allowing the addition or removal of carriages to meet customer demand.

The EMUs also accelerate the carriages faster than a diesel locomotive, speeding up schedules and enabling the 15, 20, and 30-minute schedules shown above. The more frequent trains are neighborhood-friendly since the electric motors generate no emissions and are quieter.

Following the Rail Vision report, the MBTA published an Electric Multiple Units RFI Update on June 15, 2020, which compared various vendor options from a Request for Information. Responding vendors were Alstom, Bombardier, CRRC, Hitachi Rail, Hyundai Rotem, and Stadler.

In 2021, TransitMatters published its analysis, Regional Rail Electrification: Costs, Challenges, Benefits. The report’s cost summary was:

Based on this per-mile estimate, electrification of the MBTA Commuter Rail system should thus cost $800 million to $1.5 billion. The capital cost estimates we provide cover wires, poles, and substations, but not the purchase of rolling stock. The exclusion of rolling stock is deliberate. The MBTA needs to replace its diesel and coach fleet soon regardless of whether it electrifies. As such, the fleet purchase cost should not be included in the cost of electrification itself. Electrification reduces rolling stock costs, as EMUs are cheaper than the diesel locomotives and coaches they would replace, and can be used more efficiently, so to provide the same level of service may not require as large a fleet.

2. Hybrid: Battery-electric multiple units (BEMU)

Given the high cost of installing overhead electric wires (catenary) and the permitting delays in starting construction, the MBTA commissioned Network Rail Consulting to conduct a Discontinuous Electrification Analysis. Discontinuous means that overhead electric wires are installed where economically practical for electric train operation. Where overhead wires are impractical, the electric trains will operate on batteries.

The hybrid battery-electric trains would be designed to recharge batteries when they travel from the unwired to wired portions of the train routes (see diagram).

In the June 23, 2022, Regional Rail Transformation Update, the MBTA first prioritized implementing hybrid battery electric trains for the three Environmental Justice corridor lines: Providence/Stoughton Line, Fairmount Line, and a portion of the Newburyport/Rockport Line.

The MBTA estimates that the proposed hybrid option will “achieve all Rail Transformation goals but with a 90% reduction in [bridge] clearance projects and a more than 50% reduction in catenary [costs].”

After the initial phase of decarbonizing the Environmental Justice corridor, the MBTA proposes a hybrid system to meet the decarbonization goals for the entire regional rail system by the 2050 net-zero deadline.

Without capital, the MBTA tries innovative financing

Keolis operates the commuter trains for the MBTA under a long-term contract extended through June 30, 2026.

Recently, Keolis made an unsolicited decarbonization proposal to “procure and operate a fleet of battery-electric multiple units (BEMUs) and supporting infrastructure and facilities which will be sufficient to operate 20-minute headways on weekdays and 30-minute headways on weekends [on the 9-mile long Fairmount Line].”

The proposal will not require constructing an overhead electric wire system (OCS), as the batteries will charge at the beginning and end of the route.

According to Commonwealth Beacon, the MBTA Board approved Keolis's plan to electrify the Fairmount commuter rail line.

The contract will pay Keolis $54 million to oversee the procurement and delivery of layover tracks, additional electrical infrastructure, and a maintenance facility in Readville for an unspecified number of battery electric trains. Keolis will also arrange for the leasing of the trains themselves using a third party.
The battery electric trains are expected to begin service in early 2028… The T expects to pay $27 to $30 million a year for the train lease and operations and maintenance work…

TransitMatters endorsed the battery-electric train contract with Keolis.

Private-public partnerships to lease new trains

How will the MBTA modernize its commuter rail system and maintain it in a “State of Good Repair”?

The MBTA has requested vendor interest in a Regional Rail Future Innovative Operating Contract to find a path forward using the design-build-finance-operate-maintain (DBFOM) or public-private partnerships (P3) financing model.

In this contract, the private entity invests in the new train system and then operates and maintains it for 20 or more years. The MBTA pays the private entity a fee for successfully achieving defined goals, such as on-time schedules.

The MBTA requested vendors respond with their interest in the DBFOM innovative contracts by April 19, 2024.

Using electricity to cut out transportation’s fossil fuel use

Getting more riders to use the trains and adopting electric trains will slash carbon emissions. In a UK-centric study, “Which form of transport has the smallest carbon footprint?” Hannah Ritchie determined that an electric train (Eurostar) generated only 2% of the CO2 per person as car travel. Let’s all support train electrification and the MBTA’s efforts to make progress towards cleaner air despite legislative delays.

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