Massachusetts Bay Transportation Authority (MBTA) Massachusetts Department of Transportation
Green Line Extension Green Line Extension

The GLX Project regularly gives updates to the MassDOT Board of Directors and the MBTA Fiscal & Management Control Board (FMCB). To view the GLX presentation materials shared with these boards please visit the Fiscal and Management Control Board page of the MBTA website.

May 26, 2017

Starting the week of June 5, 2017 and over the course of approximately two weeks, contractors for the GLX Project will begin performing environmental subsurface exploration work to support the project. The work hours will be limited to weekdays from approximately 7 AM to 4 PM.

These activities will be along the proposed GLX rail corridor in Cambridge, Somerville and Medford which includes the Fitchburg Commuter Rail corridor to Prospect Street in Union Square and the Lowell Commuter Rail corridor to just beyond College Avenue in Medford. This work will include soil borings performed by both hand and drill rigs.

May 23, 2017

The MBTA Green Line Extension (GLX) Project Team has released the Final Request for Proposal (RFP) for the GLX Design Build (DB) contract to the three shortlisted DB teams that were identified in February of this year. View more information about the final RFP

April Updates, 2017

View the Keolis Early Works Construction information on the Construction Updates page.

March 17, 2017

On March 10, 2017, the Executive Office of Energy and Environment issued a Certificate on the MBTA's Notice of Project Change for the GLX project. View the Certificate on the Notice of Project Change.

January 31, 2017

On January 31, 2017, the MBTA filed a Notice of Project Change (NPC) for the Green Line Extension Project with the Executive Office of Energy and Environmental Affairs (EEA). View the Notice of Project Change.

As you know, the Massachusetts Bay Transportation Authority has been working to advance the Green Line Extension (GLX) Project, which will bring much-needed light rail service to the municipalities immediately northwest of downtown Boston. The project was subject to MEPA (Massachusetts Environmental Policy Act) review, with a Certificate being issued by the EEA on June 23, 2010, determining that the project properly and adequately complied with MEPA. Construction of the project was phased, with construction starting in 2013.

In late 2015, the MBTA reviewed the project in depth and concluded that the GLX was projecting to be significantly over budget, and could reach $3 billion in total project costs if current trends continued. The GLX was, therefore, suspended by the MBTA Fiscal and Management Control Board and the Board of the Massachusetts Department of Transportation until costs could be brought back under control. The Boards created a multidisciplinary management team and tasked it with developing a redesign of the project to reduce anticipated costs while maintaining its core functionality and benefits, as well as the environmental mitigation commitments developed through the state and federal environmental review processes.

The new design of the project continues to maintain the core functionality of the project. The project remains in the same corridor and continues to have seven stations at the same locations as those reviewed in the Environmental Impact Report (EIR). These stations, however, are considerably smaller and scaled back in size and amenities. The service levels (e.g., frequency, speed, hours of operations, etc.) remain the same. As a result, ridership and air quality benefits remain unchanged from those reviewed in the EIR.

The project also includes a Vehicle Maintenance Facility in its same proposed location, but while that facility is reduced substantially in size, it maintains its core functionality for light maintenance and storage for the additional light rail vehicles required for the extension of Green Line service. In addition, all of the environmental mitigation commitments made in the Draft Section 61 Findings continue in place. The MBTA is not proposing any new or reduced mitigation compared to that which was codified in the Draft Section 61 document.

The MBTA has prepared the Notice of Project Change for your review. The NPC presents all of the changes made to the project since it was reviewed by MEPA. The MBTA strongly believes that none of these changes result in any new or different environmental impacts compared to those that were reviewed under the prior EIR. The MBTA also believes that all of the environmental benefits associated with the project as presented in the EIR remain unchanged. Lastly, all of the mitigation agreed to previously remains intact and a commitment of the MBTA.

In light of that, we believe that no additional MEPA review is warranted and submitted this Notice of Project Change in the hopes of receiving a determination from MEPA to that effect.

EEA will now accept public comments on this document. Comments should be addressed to:

Secretary of Energy and Environmental Affairs
Executive Office of Energy and Environmental Affairs (EEA)
Attn: MEPA Office
Holly Johnson, EEA No. 13886
100 Cambridge Street, Suite 900
Boston MA 02114

Comments must be received by EEA no later than 5 PM on Tuesday, February 28, 2017.

If you have any questions, or if you would like to receive a hard copy of the Notice of Project Change document, please contact the Green Line Extension project team at


There are no meetings currently scheduled.

View the presentations from the December Public Meetings:

December 7

December 14

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Construction Info

For all queries and comments related to the Green Line Extension project, please contact the project staff.

If you need project materials in alternative languages or formats, please submit your request here.

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