A scaled-back plan to extend Green Line trolley service to Somerville and Medford received tentative approval from state transportation overseers Monday.
Transportation overseers gave a unanimous, but provisional, go-ahead for scaled-down Green Line Extension project on Monday without yet fully committing the state to the $2.3 billion endeavor.
“There’s a difference between giving it the green light and signing on the bottom line,” Transportation Secretary Stephanie Pollack noted ahead of the vote.
Transportation officials had thrown the brakes on the project after cost estimates ballooned 50 percent last year to as much as $3 billion. The vote Monday gives new traction to the proposal, which would shave about $622 million from the total cost, in part, by replacing full stations with weather shelters.
Two boards overseeing the project voted to advance a scaled-down version by submitting the redesign to federal regulators and continuing with plans for financing the endeavor.
By extending Green Line trolley tracks about 4.5 miles past its current terminus in East Cambridge, the project would add service to Somerville and Medford and increase ridership by an estimated 50,000 passengers per day.
The major expansion would fulfill the state’s clean air commitments associated with the Big Dig highway project, according to Pollack, and provide long-sought mitigation for Somerville and Medford residents living close to Interstate 93.
Pollack said her priority is the roughly 1 million daily riders on the current MBTA system, and she said she wants to ensure that pursuit of the expansion project would not come at the expense of addressing the system’s maintenance backlog – estimated recently at more than $7 billion.
“If we can do both, we should do both,” Pollack said.
The move Monday, greeted with applause after hours of discussion and public comments, pushes off a decision and potential disagreement among officials charged with overseeing the expansion if a funding gap, characterized as “at least $73 million,” remains or increases.
“I would just take the $73 million and spend it,” said Russell Gittlen, the labor representative to the Massachusetts Department of Transportation Board of Directors who supports the project.
Gittlen was challenged by Pollack to identify where the state would find the extra money. “You need to specify where it comes from,” said Pollack, who has emphasized her commitment not to repeat the mistakes of the prior administration that led to cost overruns.
After the meeting Gittlen reiterated his position to the News Service, saying, “I’m good with $73 million,” and, “If it’s 73, they got my vote.”
Both the MassDOT board and the MBTA’s Fiscal and Management Control Board agreed late last year not to commit any more state money above the state’s prior commitment of roughly $1 billion. The Federal Transit Administration previously awarded a $1 billion grant, but Pollack said the federal administration would need to approve a new financing plan for the state to gain access to that.
Robert Moylan, a member of the MassDOT board, indicated he wanted to keep the earlier commitment to fiscal prudence.
“We should all be cognizant of the vote you took in December that we put a cap on this project,” Moylan said. “The project will be denied on its own weight if it doesn’t come in with that budget.”
Moylan told the News Service Gittlen was “firm” in December on the need to “hold the line” on the project. The former Worcester public works commissioner shook his head no when asked if he saw room in the $14.3 billion five-year draft capital plan to cover the $73 million difference.
Other sources of funding have been tapped to bridge the financing gap. Last week Cambridge and Somerville pledged a combined $75 million for the project, while a group that controls federal highway dollars moved $152 million into the project.
Braintree Mayor Joe Sullivan, a member of the MassDOT board, said Medford is in discussions with Tufts University, located near the proposed terminus of the planned expansion at College Avenue, about a private contribution to the project.
Somerville Mayor Joe Curtatone said, “That Tufts conversation’s still being had.”
Many have advocated for a further extension of the project one stop beyond the College Avenue location.
Jim McConnell, executive vice president of the consultancy Ascent, laid out a plan for a 40-to-50-person wing within the MBTA to oversee the Green Line Extension procurement, allowing the rest of the transit agency to focus on the day-to-day needs of the aging system.
McConnell said the prior management relied heavily on consultants who “took full advantage.”
“We also during our work found problems with the leadership, the management, the organization and the culture,” said McConnell of the prior project oversight undertaken during the Patrick administration.
“But everything else was fine,” Pollack deadpanned.
In addition to seeking feedback from the Federal Transit Administration, board members asked for regular check-ins and requested the T to begin recruiting a team to oversee the project.
“Let’s move forward as if we’re doing the project,” said Joe Aiello, the chairman of the MBTA Fiscal and Management Control Board. He said the staff could be reassigned to other capital projects if the Green Line Extension is halted.
Rafael Mares, a vice president with the environmental group Conservation Law Foundation, critiqued the interim project manager, Jack Wright, who he said avoided looking at the potential savings that could be realized through more extensive closures of commuter rail service along the project route.
The trolley extension would follow the path of the Lowell commuter rail with a spur running alongside the commuter rail tracks to Fitchburg. Wright said there are “political” and “inconvenience” costs to expanding commuter rail disruptions beyond the weekends.
“What you’re looking at is an unwillingness by this administration to look at all the cost reductions that are here because they want to protect some of their constituency,” Mares told reporters. Mares said Lowell riders could be put on an express bus from West Medford and the potential savings in the range of hundreds of millions of dollars make broader service interruptions worth study.
Leominster Mayor Dean Mazzarella, a member of the MassDOT board, told the News Service that commuters from his area have “already been impacted” by work on the extension over the past three years.
A scaled-back plan to extend Green Line trolley service to Somerville and Medford received tentative approval from state transportation overseers Monday. 
