News & Events

GZA congratulates the MBTA and GLX Constructors on opening of the Green Line Extension (GLX) branch to Union Square, Somerville

At a Glance

GZA GeoEnvironmental Inc. (GZA), a leading multi-disciplinary firm providing geotechnical, environmental, ecological, water, and construction management services, congratulates the Massachusetts Bay Transportation Authority (MBTA) and the GLX Constructors (GLXC) design-build team on the successful opening of the Union Square branch of the long awaited Green Line Extension (GLX).
The $1.3 billion, 4 ½ -mile GLX design-build project extends the existing Green Line from Lechmere Station in Cambridge to Tufts University in Medford, Massachusetts. The project includes seven new stations a new vehicle maintenance facility and renovation/replacement of 6 bridges over the track alignment. The Medford Branch extending to Tufts University – set to open later this year – will provide greatly improved MBTA rapid-transit service to Somerville, Medford, and other communities north of Boston for more than 50,000 riders daily, significantly reducing vehicle emissions. 

The GLX project, the first new MBTA subway branches to open since the Orange Line’s Southwest Corridor in 1987, also includes a community path for pedestrians and bicyclists linking to a network of paths that extend into Arlington and Bedford.

GZA has provided geotechnical design and construction phase services, retaining wall design, and geotechnical monitoring to the GLXC Design Build Team, which includes Fluor, The Middlesex Corporation, Herzog, Balfour Beatty and their design firms.

One of the innovative solutions developed by GZA on the GLX project was the use of permanent ground anchors and a soil nail wall to replace an existing granite block abutment at the Lowell Street Bridge, while maintaining traffic on the existing bridge. Not only did this accelerate construction, but it also eliminated the lengthy inconvenience to local residents of rerouting traffic around a bridge that would otherwise need to be replaced.

“GZA is proud to have been part of the outstanding Design Build Team over the last four years and congratulate the MBTA and GLXC on achieving this important milestone.  We also look forward to the opening of the remainder of the project that extends to Tufts University in Medford,’’ said GZA project principal Robert Palermo, PE, a 44-year veteran of the firm. As a client sector lead on infrastructure projects, Palermo has been involved in some of the largest and most complex projects ever completed by GZA across the country, including the Second Avenue Subway and Number 7 Line in New York City, the new Tappan Zee Bridge in New York, and the 1980s transformation of the MBTA’s North Station, through which GLX trains will travel heading to and from Boston. 

GZA CEO Patrick Sheehan said “GZA has a long history of playing important roles on major infrastructure projects, and we were happy to contribute so significantly to the Green Line Extension project.  We congratulate MBTA, GLXC, and the entire design team on achieving this important milestone.  The design and instrumentation efforts were led by Bob and other key principals and senior staff including Brad Roberts, PE, Terese Kwiatkowski PE, Rasim Tumer PE, and Michael Smith, PE.  They are all proud of their contributions and I thank them for their dedication and for bringing their significant skills to bear to help make this transformational project a reality.”