Layla Kennington | Cambridge Day

“After five decades of discussion, the MBTA has unveiled concrete plans for a connector between the blue subway line and red, which has six stations serving Cambridge and Somerville.

In public hearings Oct. 16 and 19, the transit agency outlined plans for extending blue line tracks to the station at Charles/MGH in Boston – one stop from Cambridge. As discussed in a presentation, the connector is intended to reduce travel time and the number of transfers, as well as increase accessibility for riders.

The estimated cost of the project is $850 million. Completion is expected in 2031, though deadlines and speed have not traditionally been hallmarks of the Massachusetts Bay Transit Authority.

The connector has been on the MBTA’s radar since 1972, when the concept was outlined as part of a moratorium on expressways within Route 128. The idea has come up time and time again, with a 1986 Connector study, 1990 Third Harbor Tunnel Commitment and 2010 Draft Environmental Impact report and revisions.

The connector is outlined in an MBTA 5-year Capital Investment Plan approved by its board of directors July 27, starting with $15 million dedicated to design and engineering work associated with the connector. (A cost update is expected at the 15 percent design stage.) Instrumental in the securing of these funds was transportation advocate group Transit Matters, which has drawn attention to the connector’s necessity through a series of initiatives including events, campaigns and published think pieces.”