GLX Construction is Underway

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

  • Latest Updates & Alerts

  • Detours

  • Upcoming Events

  • Background & Planning

  • City Presentations

  • Additional Resources

  • Who to Contact

Green Line Extension

Slideshow: Hover to change images, or view all here.

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, 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

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.

Updated 11/30/2018

  • Beginning in January, buildings at three sites will be demolished: First, on 3rd Ave., where a vehicle maintenance facility will go; next, the Homans Building, which will provide an off-road staging area during GLX construction; and then at the Broadway / Boston Ave. intersection, where the future Ball Sq. Green Line station will be.
  • Demo at 3rd. Ave. is expected to begin around the first week of January. Abatement there and at the Homans Building is already underway.
  • Within the rail right-of-way, crews continue drainage installation work, as well as the construction of retaining walls, noise walls, and a separation barrier to protect workers from the commuter rail. See the MassDOT biweekly construction outlook for more details.
  • Verizon has also been on the Broadway Bridge relocating conduit in advance of the bridge's demolition next year. They're expected to be finished there by the middle of the week.
  • The Broadway Bridge is scheduled to close in March, and bridges on Washington St. and Medford St. will close shortly thereafter.

Updated 11/28/2018

The Broadway Bridge, between Ball and Magoun squares, is now expected to close beginning in March 2019 for a full year. Bridges on Washington St. and Medford St. will also close for varying periods of time later in 2019.

This updated timeline is a result of the design-build process: As the project's design progresses, construction timelines and sequencing may change. The new schedule for the Broadway Bridge closure will not affect timelines for the other 2019 bridge closures or the completion of the overall project.

GLX Gantt chart thumbnail links to PDF


Updated 10/24/2018

GLX Constructors will be working overnight tonight, Wednesday, October 24, and Thursday, October 25, within the MBTA rail right-of-way between the Medford St. / Pearl St. intersection and the Washington St. / Joy St. intersection. During these times, crews will primarily be placing crushed stone known as “ballast” on the tracks and tamping it down beneath the rails. You may hear noise from trucks and other heavy equipment, but the work shouldn’t be excessively loud. Bright lights will be used within the work zone. 

As a reminder, overnight work is also planned for this coming Friday, Saturday, and Sunday nights, October 26 to 28, between the Lowell St. and Washington St. bridges. Construction activities will include track grinding and leveling, heavy-equipment hauling, and pouring and spreading more ballast. These operations will include bright lights and can be noisy at times.

We apologize for the short notice about this schedule change. Working overnight this Wednesday and Thursday will allow GLX Constructors to finish the overnight work this weekend more quickly.

Daytime work will continue seven days per week. If you have questions or concerns, please email [email protected], or call 1-855-GLX-INFO (459-4636).


Updated 10/18/2018

For the next two weekends, including the weekends of October 19 and October 26, overnight work is planned for Friday, Saturday, and Sunday nights between the Lowell Street and Washington Street bridges. GLX Constructors will be conducting track work and sporadic utility installation within the MBTA right-of-way, with most of the work taking place between Lowell St. and Central St. and near Washington St.

Construction activities will include track grinding and leveling, heavy-equipment hauling, and pouring and spreading of crushed stone. These operations will include bright lights and can be noisy at times. 

Daytime work will continue 7 days per week. Please note that the City’s normal weekend construction hours are Saturdays from 9 a.m. to 7 p.m., but work within the rail right-of-way is not subject to the City ordinance and is therefore legal to occur outside of our ordinance requirements.

If you have questions or concerns, please email [email protected], or call 1-855-GLX-INFO (459-4636).


Updated 9/27/2018

Videos of the August 29 and September 24, 2018 community meetings regarding the one-year closure of the Broadway Bridge are available at the links below:

Updated 8/30/2018

The City's presentation from the August 29, 2018 information session regarding the one-year closure of the Broadway Bridge is now available online.

Update 8/24/2018

On Saturday, August 25 and Sunday, August 26, between the hours of 7 a.m. and 9 p.m., GLX Constructors will be conduction demolition of an abandoned concrete pier adjacent to the Medford St. Bridge in Gilman Square, between Walnut St. and Pearl St. Because the work will require use of heavy demolition equipment like jackhammers and rammers, the work is expected to be loud in the immediate vicinity for at least the morning hours on Saturday. The work will be conducted in the rail right of way, and therefore no traffic impacts are expected.

Please note that the City’s normal weekend construction hours are Saturdays from 9 a.m. to 7 p.m.; however, work within the rail right of way is not subject to the City ordinance and is therefore legal to occur outside of our ordinance requirements.

Updated 8/14/2018

GLX Community Meeting to Discuss  Upcoming Bridge Closures, August 29

Although timelines are subject to change, current plans for the construction of the Green Line Extension (GLX) call for the full closure of the Broadway Bridge, just east of Ball Square, for one full year beginning in late 2018. While the bridge is closed, detours will be in place for cars, bikes, pedestrians, and MBTA bus routes 80 and 89.

Please join City of Somerville staff, Ward 5 Alderman Mark Niedergang, Ward 6 Alderman Lance Davis, and representatives from the GLX team for a community meeting on Wednesday, August 29, at 6 p.m. to discuss the upcoming bridge closure and detour routes. The meeting will be held at the Somerville Community Baptist Church, 31 College Ave.

Additional temporary bridge closures for varying periods are also planned for later construction phases in 2019 and 2020, including on Washington St. (between Union Square and Inner Belt), Medford St. (outside of Union Square), and School St. The meeting will touch upon these, but the Broadway Bridge closure will be the longest, most complex, and likely most impactful of all the bridge closures planned. This meeting will, therefore, focus primarily on upcoming construction and mitigation efforts in the Ball Square neighborhood this fall and through 2019.

For more information, including the latest proposed detours, please visit or

Individuals with disabilities who need auxiliary aids and services for effective communication, written materials in alternative formats, or reasonable modifications in policies and procedures, in order to access the programs and activities of the City of Somerville or to attend meetings, should contact the City’s ADA Coordinator, Nency Salamoun, at 617-625-6600 x2323 or [email protected].

Updated 7/30/2018

MassDOT Meeting Presentation Materials Now Available

On July 18, 2018, MassDOT held a public meeting at Medford City Hall to provide updates and information on the GLX project.

You can view the full meeting presentation by clicking here. Key excerpts include:

Upcoming Work

On Saturday, August 4, GLX subcontractors will begin tree removals along the west/north side of the rail corridor, between Cross St. and Broadway. Work will be conducted on Saturdays and Sundays throughout the month of August and will progress from the south (Cross St.) to north (Broadway). Work will be conducted between 6 a.m. and approximately 6 p.m. on Saturdays and Sundays.

Though the remainder of tree removals was originally scheduled to begin in early 2019, construction crews recently discovered that more tree work is necessary to facilitate construction of drainage systems along the rail right of way before more significant construction on retaining walls and building new tracks around the existing commuter rail line can begin. Due to the nature of the work, tree removals must begin earlier than anticipated. Additionally, following recent severe storms, a number of the remaining trees along the existing commuter rail line were heavily damaged and fell onto or near the tracks, creating hazardous situations.

If you have questions about this work, please visit, email [email protected], or call 1-855-GLX-INFO (459-4636).

Updated 7/5/2018

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

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.




While all dates are subject to change, the Broadway Bridge, just east of Ball Square, is scheduled to close for one full year beginning in March 2019 to accommodate construction. All modes of transportation will be detoured during that time, including cyclists and pedestrians. Later in the spring of 2019, bridges on Washington St. and Medford St. will also close for varying periods of time.

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

Check back soon for more events.


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.

Community Meeting/Info Session Re: Broadway Bridge Closure

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’s GLX Liaison, Viola Augustin, coordinates technical and logistical issues related to construction. She can be reached at [email protected] or (617) 625-6600 ext. 2520.

Si w bezwen enfòmasyon an kreyòl Ayisyen kontakte Jhenny Saint-surin nan 617-625-6600 ext. 2622.

Si necesita esta información en español contacte a Irma Flores al 617-625-6600 ext. 2122.

Se necessita desta informação em português, contate Adriana Fernandes no 617-625-6600 ext. 2123.