The long-awaited debut of the Green Line Extension’s service to Somerville is right around the corner. — Photo courtesy of MBTA GLX

By Jim Clark

After many years of planning, controversy, and delayed construction, the new Green Line Extension (GLX) service will begin operating in the City of Somerville starting on March 21.

Last Thursday, MBTA General Manager Steve Poftak made the official announcement setting the date for GLX service to Union Square to get underway.

Other stations along the two main branches are expected to come online later this year, hopefully by summer if not sooner.

A grand opening ceremony is planned for the March 21 date at the Union Square station.

The purpose of the GLX construction project is to extend the light rail Massachusetts Bay Transportation Authority (MBTA) Green Line northwest into Somerville and Medford. The project is expected to fully open in 2022 at a total cost of $2.28 billion. Total ridership on the 4.3-mile (6.9 km) extension is estimated to reach 45,000 one-way trips per day in 2030.

In 2015, with projected costs increased to $3.3 billion, the project was placed on hold. A revised plan, with more modest stations and other value engineering, was submitted in 2016 and approved in 2017.

The main $1.08 billion design-build contract was issued in November 2017, with several optional items like platform canopies and a larger vehicle maintenance facility included. Construction began in 2018, with the old Lechmere station closed in May 2020.

The cities of Somerville and Cambridge are expected to be reimbursed for the combined $75 million they contributed to the project when budgetary issues threatened to derail its completion.