Green Line Extension Hits Major Milestone as GLX Reaches Somerville

The Massachusetts Bay Transportation Authority's Green Line Extension reached a pivotal moment on Wednesday when service officially commenced to the newly completed Union Square Station in Somerville, ending a project that has been under construction since 2011 and facing repeated delays.

The opening represents the first of two stations set to operate on the 4.3-mile extension, which will eventually stretch from the current Lechmere terminus in Cambridge through Somerville and into Medford. The Union Square stop, located at the intersection of Somerville Avenue and Washington Street, will serve as an interim terminus until the second phase completion at College Avenue Station, currently targeted for late 2027.

"This is a transformative moment for regional connectivity," said the MBTA in a statement, noting that the extension will ultimately provide service to approximately 40,000 residents in underserved communities. The project, which has cost roughly $2.3 billion—significantly exceeding initial estimates of $1 billion—nevertheless promises to reshape commuting patterns across Greater Boston.

The new station features an elevated platform design with modern amenities including real-time passenger information systems and accessible boarding areas. Transit officials expect the extension to generate approximately 10,000 daily riders upon full completion, reducing car traffic on Massachusetts Avenue and other major thoroughfares in the region.

The opening comes as the MBTA grapples with broader infrastructure challenges across its network. Service reliability metrics show the agency has struggled with aging infrastructure on existing lines, including the aging Red Line infrastructure and ongoing signal system upgrades on the Blue and Orange lines.

For Somerville residents, the development offers long-awaited transit access. The city, home to technology companies and universities including Tufts, has experienced significant residential growth over the past decade. Real estate analysts note that proximity to transit stations has already begun influencing property values in the Union Square area, with some commercial rents climbing 15-20% in the past year.

Phase two of the extension will add the College Avenue Station in Medford, bringing the project to full completion. While the original timeline envisioned completion by 2021, project managers attributed delays to complex utility relocations, permitting challenges, and the impacts of the pandemic on construction schedules.

The success of the GLX remains critical for the MBTA's broader transit agenda, as the agency works to modernize aging infrastructure and meet state transportation goals targeting reduced vehicular emissions in the Boston metropolitan area.

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