About the Green Line Extension (GLX) Project

Bulldozer levels ground for GLX track

GLX Construction is Underway

For detailed project information, visit the MassDOT GLX Project page.

  • Latest Updates & Alerts

  • Upcoming Events

  • Background & Planning

  • City Presentations

  • Additional Resources

  • Who to Contact

With so many groups partnering on this project, there are a number of ways to stay informed. Here’s a summary of existing information channels:

1. This Page and City Alerts: The City of Somerville is committed to providing transparent, efficient, and comprehensive communication to residents throughout GLX construction. City-specific coverage will include information about construction updates and subsequent impacts that are most relevant to constituents, as well as announcements about upcoming related events and other resources, such as detour maps, as they become available.

This page and City alerts are intended to supplement, not replace, broader outreach efforts from the GLX project team and the MBTA/MassDOT. We encourage you to sign up for those so that you’re fully in the know. 

2. MassDOT / GLX WebsiteVisit greenlineextension.org, where you can find construction updatesprogress photos, and full project background materials.

3. MassDOT / GLX Email Updates

MassDOT and the GLX team maintain an email list, available to anyone wishing to opt in. Emails include upcoming schedules and work information. To sign up for these email updates, visit www.greenlineextension.org.

3. Station-Area Representatives

The GLX project team developed a Community Working Group to enable information sharing between the project team and the public. The Working Group consists of representatives from each of the station areas in Medford, Somerville, and Cambridge. Working Group members provide assistance to the MBTA and to the community in identifying local issues of concern, facilitating dialogue, and planning agendas and topics for discussion at neighborhood and community meetings.

We strongly encourage you to reach out to the Working Group representative closest to your area of interest and sign up for their alerts and updates. These representatives work very closely with the project team and the City of Somerville. They can provide you with valuable information for your specific neighborhood. The representatives for each area are listed below with their contact information.


Latest Updates


Bridge Closures: Timeline and Detours

While all dates and information are subject to change, current proposals by the GLX team call for the full closure of the Broadway Bridge at Ball Square, just east of Ball Square, for one full year beginning in the fall of 2018. As it stands now, the closure would apply to all modes of transportation, including bicycles and pedestrians. Additional temporary bridge closures for varying periods are also planned for later constructions phases in 2019 and 2020.

Click here to see the latest proposed timeline for bridge closures, and click on the links below to see the latest proposed detour routes:



The GLX team proposed closing the Broadway Bridge for a year -- the longest of the closures outlined -- because they’ll be completely rebuilding that bridge. They also have to conduct demolition and construction around an active Commuter Rail line, which has implications for when their work can take place. 

Detour routes are still under review. City staff, Community Working Group members, MassDOT, MBTA, and GLX Constructors continue to discuss the proposed closures at monthly Community Working Group meetings. Meeting presentations and minutes are posted at http://greenlineextension.eot.state.ma.us/CWG.html

Ultimately, detour routes will be produced for local traffic, regional traffic, cyclists, pedestrians, and MBTA buses. City representatives have been working closely with first responders, school officials, and local businesses to develop plans to accommodate restricted access to Ball Square. They’re also working to understand longer-term considerations for routine City services like trash pickup, street sweeping, and snow plowing, as well as how GLX work will interact with utility projects and other City construction. We will provide more information as it becomes available.

Homans Building Demolition

The Homans building at 358 Medford Street in Gilman Square is scheduled for demolition this summer. Contractors are working closely with Somerville’s Historic Preservation Commission to ensure agreed-upon portions of the structure are preserved. Stay tuned for more information about a community-led event that will mark this new era for Gilman Square.


GLX Meeting Schedule Flyer

Drop-In Q&A Opportunities with GLX & City of Somerville Representatives

  • Saturday, July 14, 11 a.m., at the ArtBeat event in Davis Square
  • Thursday, July 26, 4:30 - 6:30 p.m., Magoun Square

Thanks to all those who stopped by our first drop-in Q&A event in Ball Square! Keep an eye out for the City’s GLX information table at ArtBeat and other community events throughout the summer. Check back here soon to see a schedule of more upcoming Q&A opportunities.

GLX General Public Meeting
Wednesday, July 18, 6:30 – 8 p.m., Medford City Hall

This meeting is expected to cover primarily bridge closures and Community Path updates. Please note that meeting organizers have indicated that no new information will be presented at this meeting. Everything discussed will be information that has already gone out to Community Working Group members.

Preparing Your Business for Construction
Friday, July 27, 10 a.m. – 12:00 p.m., Somerville Public Library, 79 Highland Avenue

Between the Union Square Sewer Separation and the Green Line Extension, many Somerville businesses will be contending with the disruptions associated with construction. Thanks to Revolution Capital and New Leaf Legal, we are able to offer this free workshop to help small business owners assess risks to their business from construction. With the assistance of professionals in business law, commercial insurance and financial planning, business owners will explore steps they can take in advance to prepare their businesses for common problems.

Our professional experts include Jessica Manganello, JD, an experienced business attorney and a founding partner of New Leaf Legal, LLC; Douglas Soons, JD, an investment manager and property & casualty insurance agent with Revolution Capital, Inc.; and Amy Witherbee, JD, PhD, a financial planner and investment manager with Revolution Capital, Inc.

Click here to RSVP


GLX Vision MapAfter decades of advocacy, construction on the Green Line Extension is finally set to begin.

The GLX 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. By the close of 2021, Somerville’s five new T stations will be up and running in Union Square, East Somerville, Gilman Square, Magoun Square, and Ball Square. Trains will operate every five to six minutes in the peak periods, providing fast and efficient service to downtown Boston. The Somerville Community Path will also be extended from Lowell Street to Inner Belt Road. 

The T extension is a key priority outlined in SomerVision, the City’s 20-year plan to make Somerville an exceptional place to live, work, play, and raise a family. Currently, 15% of the City’s population resides within half a mile, walking or biking, of a transit node. When the GLX is operational, that number will climb to 85%. We stand to see improvements not only to our infrastructure but to our collective health as a community -- physically, economically, socially, and environmentally.


For Somerville, the fight for the Green Line Extension has been a fight for environmental justice and transportation equity. In 1990, Massachusetts agreed to extend the Green Line to offset the pollution increase within Somerville caused by the Big Dig. Despite this legal commitment, however, the Green Line Extension project lagged far behind schedule, prompting the City of Somerville and the Conservation Law Foundation to file a lawsuit to keep the project moving.

In 2006, this litigation, with the help of community support and advocacy groups, finally brought about a multi-million dollar state investment in the Green Line extension from Lechmere Station into Somerville and Medford.

Community involvement has played a large role in the initiation and planning of this project, and it will continue to be a priority as construction moves forward. The GLX Community Working Group, consisting of representatives from Somerville, Medford, and Cambridge, provides guidance and input to the Executive Office of Transportation and Public Works. STEP, the Somerville Transportation Equity Project, has also been involved throughout the process, ensuring that the extension will result in social equity, environmental health, and decreased population to improve the health of Somerville residents.

Past Community Correspondence

Green Line Maintenance Facility

Joseph A. Curtatone
December 29, 2008

Green Line Maintenance Facility

Joseph A. Curtatone
September 12, 2008

Green Line Station Concepts

Monica R. Lamboy
September 12, 2008

Questions? Here’s who to contact.

GLX 24/7 Hotline: The GLX team is happy to assist you. This is the best first stop for any questions or concerns. Call the project hotline 24/7 at 1-855-GLX-INFO (459-4636) or email them at[email protected].

311 Constituent Services: For basic City-specific issues related to the GLX, contact our 24/7 Constituent Services Office at 3-1-1 (or 617-666-3311).

City of Somerville Economic Development: Local businesses with questions, concerns, or ideas can email Lauren Drago ([email protected]) and/or Nick Schonberger ([email protected]), or call the department at (617) 625-6600 ext. 2500.

City of Somerville GLX Liaison: The City is in the process of hiring a project liaison to coordinate technical and logistical issues related to construction. For now, additional City staff assigned to the project are available to assist you via [email protected] or 617-666-3311.