Don’t expect shovels in the ground overnight, though. Officials said a long-range planning document would include a pledge to build the link by 2040 — and there’s no set timeline for the connector between now and then.

After months of lobbying by activists and elected officials, the Massachusetts Bay Transportation Authority on Monday made a fresh commitment to building the so-called Red-Blue connector, a project that had been shelved for years.

The MBTA’s next subway expansion project will link the only two branches that don’t connect today by extending the Blue Line tunnel 1,500 feet under Cambridge Street to Charles/MGH Station on the Red Line.


“This is a twenty-plus-year plan,” state Transportation Secretary Stephanie Pollack said at a meeting of the T’s oversight board. “It is not intended to imply that every next-priority project in it will be started next year. In fact, it’s not possible.”

Nonetheless, the decision cheered activists and officials, who lined up at the meeting to demand that the authority prioritize the project. Over the last year, the T had said only that it would consider building the link sometime after 2040.

“This is music to our ears,” said Gina Fiandaca, Boston Mayor Martin J. Walsh’s transportation commissioner. The mayor is a supporter of building the rail link.

Some proponents of the project — including a former state transportation secretary, Frederick P. Salvucci, and Staci Rubin, an attorney with the Conservation Law Foundation — called on the MBTA to build sooner rather than later.

And one member of the T’s five-person board of directors, Brian Lang, said planning should begin immediately.

“I’m absolutely convinced we have to move on to the Red-Blue connector. I think it’s urgent,” Lang said. “We as a board need to go through whatever process it is that gets money into the budget in 2019 for engineering and environmental reviews.”


Even putting the connector on pace for 2040 marks something of a Lazarus-like revival for a project that — like the long-awaited Green Line extension to Somerville that’s now under construction — was once promised to offset the environmental impacts of the Big Dig project, which put the elevated Central Artery through downtown Boston into tunnels.

But Massachusetts officials, under then-governor Deval Patrick, asked for federal permission to abandon a requirement that they design the project, citing high costs. Federal officials approved the request in late 2015, after Governor Charlie Baker had taken office.

Under Baker, the MBTA has typically not entertained subway expansions. But calls for the Red-Blue connector resurfaced in 2017 with the nationwide sweepstakes to land a second Amazon headquarters. Walsh made a pitch to the tech giant for it to build a campus on the East Boston-Revere line at the Suffolk Downs racetrack. Members of the T’s board then asked for new research into potential costs.

That study determined that, depending on the tunneling method, the project could cost much less than previously expected: $200 million to $350 million.

As part of its renewed commitment to a Red-Blue link, the T on Monday dropped a proposed stopgap measure — building a pedestrian tunnel between State Street Station on the Blue Line and the Downtown Crossing Station on the Red line — to facilitate a downtown connection.

Activists called that idea a poor substitute for a connection at Charles/MGH, and the advocacy group Transit Matters collected more than a thousand signatures calling for the Red-Blue connector.


In the coming years, officials say, new cars and updated signal technology will allow the T to run more frequent service on the Red Line, with a larger fleet of vehicles. The Blue, meanwhile, is the only subway line on which ridership has grown in recent years, though vehicle traffic on the North Shore and in East Boston has also ballooned.

On Monday, city councilors from Boston, Revere Mayor Brian Arrigo, and state lawmakers from the North Shore and East Boston voiced their support for linking the two lines. House Speaker Robert DeLeo, whose Winthrop district is near the Blue Line, submitted a letter to the T saying a connection would ease traffic congestion by making it easier to commute between the North Shore and Cambridge.

Brendan Crighton, a state senator from Lynn, said the state should also plan to extend the Blue Line in the opposite direction, to his city — another long-proposed expansion that, according to the long-range plan, the MBTA may consider after 2040.

The long-range plan, which will be finalized this month, also anticipates that by 2040 the T will have purchased new high-capacity Green Line trains, extended Silver Line bus service to Everett, shifted to a zero-emissions bus fleet, and built the West Station transit facility in Allston.


Adam Vaccaro can be reached at adam.vaccaro@globe.com.