Green Line Extension (GLX)

A Green Line train approaches Lechmere at dusk (March 2022)

The Green Line Extension (GLX) will extend the northern end of the Green Line from Lechmere to Union Square in Somerville and College Avenue in Medford.

Contract awarded: November 2017
Projected completion: Summer 2022
Budget: $2.3 billion
Status: Construction

GLX will provide service in areas that historically did not have access to fast and reliable public transit. By supporting an increased ridership of more than 50,000 trips per day, this project will significantly reduce vehicle emissions on the road.

Building a Better T

As part of our $8 billion, 5-year capital investment plan, we're renovating stations, modernizing fare collection systems, upgrading services for our buses, subways, and ferries, and improving the accessibility of the entire system.

Learn more

Project Features

A new Green Line branch on existing Lowell Commuter Rail tracks, from Lechmere to Medford
A new Green Line branch on existing Fitchburg Commuter Rail tracks, from Lechmere to Union Square in Somerville
The relocation and reconstruction of Lechmere station in Cambridge, plus six new additional T stations
A new vehicle storage and maintenance facility

View GLX stops on system map

Rider Benefits

Create additional transportation routes in the Medford and Somerville neighborhoods
Reduce the number of vehicles on local roads to improve traffic concerns
Support municipal plans for sustainability and urban redevelopment

How to Pay for Your Fare

At Lechmere and Union Square stations, all riders will need to validate their CharlieCards or tappable CharlieTickets at a fare vending machine prior to boarding, or use the fare box at the front of the train. Please note that old, insertable CharlieTickets can only be validated at onboard fare boxes.

Learn more about how to validate your fare

What to Expect During Construction

Two test trollies arrive and depart the new Union Square station. The station was under construction at the time the trollies were tested, so traffic cones and a temporary chain link fence sit on the platform between the two trains. — Test trollies arrive at and depart from Union Square station prior to its opening (January 2022)

Green Line Service Changes

Beginning Monday, March 21, Green Line service between North Station and Lechmere will resume, and regular service on the Union Branch will begin.

B and C Branch trains will terminate at Government Center
D Branch trains will terminate at North Station
E Branch trains will terminate at Union Square

See Green Line maps and schedules

See Green Line service alerts for current service information

Upcoming service changes

After the Medford Branch opens:

E Branch trains will terminate at Medford/Tufts
D Branch trains will terminate at Union Square

After the Medford Branch opens:

E Branch trains will terminate at Medford/Tufts
D Branch trains will terminate at Union Square

Commuter Rail Service Changes

Commuter Rail service may shut down periodically along various portions of the Lowell Line to support this work. Shuttles will replace trains during these times.

See service alerts for the Lowell Line

Bridge Closures


Location	Status	Schedule
Location	Washington Street Bridge/Underpass	Status	Open	Schedule	Reopened May 31, 2020.
Location	Broadway Bridge	Status	Open	Schedule	Reopened June 6, 2020.
Location	Medford Street Bridge	Status	Closed	Schedule	Work is ongoing. Expected to reopen in April 2022.
Location	School Street Bridge	Status	Closed	Schedule	Work is ongoing. Expected to reopen in May 2022.