Massachusetts Bay Transportation Authority


Cambridge, Somerville & Medford, MA


Rail Transportation: Line Segments & Tunnels 


Design: Architecture, Civil Engineering, Electrical Engineering, Mechanical/HVAC Engineering, Geotechnical Foundations, Plumbing/Piping/Fire Protection, Structural Engineering, Industrial Engineering, Utility Relocation

Green Line Light Rail Extension

STV is serving as the lead designer for the Massachusetts Bay Transportation Authority’s (MBTA) $1.3 billion Green Line Light Rail Extension (GLX) as part of the design-build team led by Fluor Corporation/Middlesex Corporation/Herzog Contracting Corp/Balfour Beatty joint venture (GLX Constructors).

The 4.3-mile extension will provide the Massachusetts communities of Cambridge, Somerville and Medford with a one-seat ride to downtown Boston. The program includes the design and construction of a new vehicle maintenance facility, an administration building, a viaduct, six new stations, one relocated station, six bridges, and a community path.

The MBTA anticipates a number of benefits for the project, including the reduction of 26,000 regional daily vehicle miles travelled, thereby improving air quality and reducing automobile congestion in the commonwealth. Daily ridership at the seven new GLX stations – which will all be outfitted with amenities that meet or exceed Americans with Disabilities Act standards – is expected to hit 45,000 by 2030. Additionally, all GLX operations will take place within an existing railroad right-of-way, the 3.4-mile Lowell Line and 0.9-mile Fitchburg Line, which minimizes the need to purchase additional ROW.