Green Line Extension Design-Build - Middlesex Corporation

Green Line Extension Design-Build

Cambridge, Somerville, and Medford, MA
Massachusetts Bay Transportation Authority (MBTA)

Relocation of 3.4 miles of NH Main Line double track and the construction of new Medford Branch Green Line tracks

This project will extend the MBTA Green Line from a relocated Lechmere Station in East Cambridge to Union Square in Somerville and College Avenue in Medford. There will be seven new stations constructed as part of the project, including the relocated Lechmere Station. A vehicle storage and maintenance facility will also be constructed. In addition to the infrastructure needs of the project, an extension of the Somerville Community Path between Lowell Street and Inner Belt Road in Somerville. Once completed, trains will operate every five to six minutes in the peak periods, providing fast and efficient service to downtown Boston.

Project Numbers


Project value

92,400 SF

Noise wall

46,100 SF

Retaining wall

4.3 Miles

New light rail

16,500 LBS

Structural steel