Press Release

Balfour Beatty joint venture celebrates the opening of the Green Line Extension’s final branch

13 December 2022


Balfour Beatty, as part of Green Line Extension (GLX) Constructors joint venture, celebrates the grand opening of the $1.1 billion (c.£ 896 million) Medford Branch, the last line completed during the construction of the Massachusetts Bay Transportation Authority’s (MBTA) GLX project in Massachusetts, US.

The Medford Branch is the final line of two developed along the 4.7-mile light rail and follows the completion of the Union Square line in Somerville which began revenue service earlier this year to  provide an enhanced travel experience for passengers and allow a more reliable, sustainable and urban redeveloped public transit service in the Boston area.

To successfully open the Medford Branch, the joint venture team constructed five stations on the existing Lowell Commuter Rail corridor and worked to advance final phase construction elements along the light rail including:

  • Adjustments to the overhead wire on the East Cambridge Viaduct that will eliminate a temporary 10 mph speed restriction, allowing trolleys to operate at the system’s designed speed of 25 mph on a permanent basis. The higher speed is necessary to maintain proper schedule intervals as five new Medford Branch stations are added to the system.
  • The final testing and integration of track switches, power lines, signal equipment, and digital communications between the Green Line’s currently operating Union Branch, the newly operational Medford Branch, and the MBTA’s Operations Control Center.
  • Completion of a nearly two-mile extension of the Community Path which provides access to other pathways leading into Boston.
  • The installation of the last remaining sound wall panels along the Union Branch and non-critical work items along the Medford Branch.
  • Additional last work and various outstanding construction items along the Union and Medford Branches’ tracks, stations, and rights of way.

Mark Konchar, Balfour Beatty Senior Vice President and Managing Director of U.S. Rail Operations said: “I couldn’t be more proud of our Balfour Beatty team and partners for officially completing the final line of MBTA’s Green Line Extension project.”

“Opening the Medford Branch is a monumental milestone in the project’s delivery along with many others that our teams worked hard to accomplish to enhance the travelling experience for thousands of passengers.

“In partnership with the MBTA, our industry partners and community stakeholders, Balfour Beatty looks forward to finishing final stages to prepare for project closeout in 2023.”

With services commencing along GLX’s new branches, the MBTA can significantly reduce congestion and related air emissions in Boston and provide communities with universal access and new stations that meet or exceed the Americans with Disabilities Act (ADA) standards. It is also expected to increase passenger capacity by more than 50,000 per day and reduce regional daily ‘Vehicle Miles Traveled’ by 25,728 miles.

To learn more about the GLX project, visit Home (


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Notes to editors:

  • Balfour Beatty is a leading international infrastructure group with 24,500 employees driving the delivery of powerful new solutions, shaping thinking, creating skylines and inspiring a new generation of talent to be the change-makers of tomorrow.
  • We finance, develop, build, maintain and operate the increasingly complex and critical infrastructure that supports national economies and deliver projects at the heart of local communities.
  • Over the last 113 years we have created iconic buildings and infrastructure all over the world including: the £1.5 billion A14 improvement scheme - Britain’s biggest road project; Hong Kong’s HK$5.5 billion world-class harbour theatre project for the West Kowloon Cultural District Authority; and the 12.5 mile $429 million North Metro Commuter Rail line in Colorado, US.
  • Balfour Beatty is an industry-leading provider of general contracting, at-risk construction management and design-build services for public and private sector clients across the United States. Performing heavy civil and vertical construction, the company is part of Balfour Beatty plc (LSE: BBY), a leading international infrastructure group that provides innovative and efficient infrastructure that underpins our daily lives, supports communities and enables economic growth.
  • Consistently ranked among the nation’s largest contractors, Balfour Beatty is the No. 6 Domestic Building Contractor in the United States as ranked by Engineering News-Record. To learn more, visit
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