A billion dollars.

That’s the potential overrun, state officials said Monday, for the Boston area’s biggest transit project—the long-planned, oft-delayed, but now-underway Green Line extension into Somerville and Medford.

The project is legally required as an environmental mitigation for the Big Dig highway tunnel project. The federal government committed last year to provide half of the funding (but with the new estimates, that’s more like a third of the costs). Plans called for the first three of seven stations—two new stops in Somerville, plus a redone Lechmere station in East Cambridge—to open in 2017.

The revelation of the exploding cost forecast, though, has brought questions about how to deal with it, if at all. The news came at a meeting of the MBTA’s Fiscal and Management Control Board, the system’s new governing body meant to tackle the broad financial and operational issues facing Boston’s transportation system.


A state presentation lists four suggestions for addressing the Green Line extension’s cost issues (and as a fifth option, asks the public to submit their ideas).

1. Change the scope. The state suggests that delaying some of the new stations could save some money, as could downsizing them. The extension of a Somerville bike and walking path that is also part of the project and a planned MBTA facility for maintenance and storage could also be places to skimp.

2. Find new money. How? Diverting federal funds from another transportation project; lobbying the feds for more cash outright; utilizing municipal financing mechanisms—such as tax increment financing—from Cambridge, Somerville, and Medford; soliciting for help from private sector stakeholders like Tufts University.

3. Change the contract process. The Green Line extension was originally put to bid as a “construction manager/general contractor’’ project, with one firm serving as the quarterback throughout construction and delivering on phased contracts as the project advances. The presentation says the project could be put back out to bid in more of a piecemeal fashion.

4. Forget about it. Secretary of Transportation Stephanie Pollack characterized this option as less than ideal. The state has already poured hundreds of millions of dollars into the early stages of the project. And backing out could expose the state to further litigation. Joshua Block, the press secretary for the Conservation Law Foundation, which sued to enforce the Green Line extension last decade, said Tuesday: “We need to learn more about the details, but what’s certain is that the Green Line extension is a legal requirement under the federal Clean Air Act that CLF has long enforced. … CLF will not abandon it.’’ But, the presentation says, walking away is an option all the same.


Read the full presentation below:

GLX Contract Presentation for FMCB Final - 08.21.2015

When Boston built the Big Dig: