T Making $13 Million Commitment Toward Building the Blue Line Extension

12:25 PM EDT on June 7, 2021

A rendering of a future Blue Line station entrance from the lobby of the existing Charles/MGH station in Charles Circle. Escalators would lead underground to a new Blue Line platform under Cambridge Street. The Red and Blue Lines are currently the only two lines in the T’s network that don’t directly connect to each other at a downtown station. Courtesy of the MBTA.

MBTA officials are finally moving forward with a long-dormant proposal to extend the Blue Line subway westward to connect to the Red Line at the Charles/MGH station, and plan to spend $13 million in earnest money this year for design and environmental permitting work for the project.

Erik Stoothoff, the T's Chief Engineer, told board members that the agency plans to hire new staff to coordinate the project, begin environmental permitting work, and hire a consultant team that can conduct early design work.

"We do have approximately $13 million in funding available (in the upcoming year's capital budget) .. for the advancement of the preliminary engineering and environmental review," said Stoothoff. "It also gives us the ability to put together a team to be able to support coordination with our partners along the corridor – the City of Boston, Mass. General Hospital, Mass. Eye and Ear Infirmary – so that we can evaluate any opportunities for early advancement of project elements in conjunction with those other projects."

If all goes well, that work could lead to a final design by 2024, a groundbreaking in 2025, and a new subway station by 2030.

A link between the Blue Line and the Red Line has been languishing on the T's to-do list since 1990, when Massachusetts promised environmentalists to build it by 2010 as part of a broad array of transit improvements deemed necessary to mitigate air pollution impacts from the “Big Dig” highway expansion.

But a planned expansion of the nearby MassGeneral Hospital, which offered the opportunity to include space for a new station entrance on Cambridge Street, appears to have helped kick-start the proposal.

A cutaway view of the new Charles/MGH subway station under Cambridge Street. The existing Red Line station above Charles Circle is visible at left; the proposed new Mass. General Hospital building, in the background at right, would provide a second entry point at the other end of the station. Courtesy of the MBTA.

According to Monday's board presentation, officials at the T think that the full project could cost about $850 million to design and build over the course of the next 9 years (for context, the MBTA is aiming to spend roughly $1.5 billion every year just on state-of-good-repair maintenance projects over the next decade).

The total cost estimate includes a $20 million line-item for streetscape work above the new tunnel, which would involve a full reconstruction of Cambridge Street between Charles Circle and Government Center.

Bike advocates have high hopes that that reconstruction can finally provide a protected bike lane connection between the Longfellow Bridge and City Hall, a notorious gap in the region's bike route network.