Boston's $3.5 Billion Green Line Upgrade to Double Capacity
System modernization would phase out old-fashioned Green Line trolley cars.
PHOTO BY JUSTIN RICE FOR ENR
Boston transportation officials on May 7 unveiled an estimated $3.5-billion plan for modern Green Line trains that could potentially double the capacity of the nation’s oldest and most heavily traveled light-rail system.
“This is an exciting moment for the T,” said Steven Poftak, vice chair of the Massachusetts Bay Transportation Authority’s Fiscal Management and Control Board, at a meeting.
The 114-ft, low-floor Concept D trains would be 40 ft longer than the antiquated trolleys now in use, according to the MBTA Green Line Transformation Program study. The longer length and elimination of ticket boxes would help accommodate up to 400 passengers.
Jeff Gonneville, deputy general manager of the authority, says nearly $1 billion is secured in capital expenditure plans, but declined to discuss specifics for the remainder of funding required. Despite the high price tag, he says the investment was worth it since the new trains would double capacity for a line that carries 200,000 people a day.
Before the trains arrive by 2028, bridges and structures, including some infrastructure up to a decade old, will need to be upgraded, Gonneville says. The 1920 Lechmere Viaduct, an 11-span concrete arch viaduct that runs from Lechmere Station to the Boston Museum of Science, is one structure known to limit capacity. “The aqueduct currently constrains trains to 20 mph and can only support two sets of trains crossing in each direction at a time,” he says.
In assessing power and signal needs for the new trains, the authority plans to study power capacity across the system to define what cable and wiring upgrades are necessary. It also plans to continue its investment of $150 million in track upgrades to a standard where it can successfully operate the new trains.
In a recent light detection and ranging study of the Green Line, “the maintenance-of-way team took a 3D model of the Concept D vehicle and implanted it into the Lidar model and ran a simulation study through the entire GL to see if there were any impact or clearance issues,” Gonneville says.
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In other news, the authority has chosen transportation design firm STV to serve as lead designer for the $2.3-billion Green Line extension. It will join the design-build team led by the Fluor Corp./Middlesex Corp./Herzog Contracting Corp./Balfour Beatty joint venture (GLX Constructors).
The 4.3-mile light-rail extension project includes two new branches, from Lechmere Station in East Cambridge to Union Square in Somerville and to College Avenue in Medford. Work is expected to begin this year. The project also calls for seven new stations, including the relocated Lechmere Station. Additional elements include the design and construction of a new vehicle maintenance facility, an administration building, a viaduct, six bridges and a community path.
