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MBTA names winning bidder for Green Line extension project

Green Line Constructors, a joint venture of several engineering and construction firms, will design and build the Green Line extension. Keith Bedford/Globe Staff

The MBTA has named the winning bidder for the agency’s largest-ever construction contract, for the 4.7-mile extension of the Green Line through Somerville and Medford.

Green Line Constructors, a joint venture of several engineering and construction firms, will design and build the additional service, which includes seven new stations from Lechmere in Cambridge to Tufts University. The company said it could build the expansion for $1.08 billion, well below a maximum price required by the T, and has promised to restore portions of the project that were previously cut like a key portion of a bike lane, elevators, and a vehicle maintenance facility.

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The award, which must be formally approved by the agency’s board later this month, marks a significant milestone for the long-planned and long-delayed rapid transit project that underwent substantial changes after ballooning costs threatened to kill it altogether in 2015.

Green Line Constructors was chosen from between two finalists for the contract. It had the lower of the two bids, but price was not the only factor: the winner was chosen based on who offered the best value while staying under an agency-mandated limit of $1.3 billion. The agency used a scorecard to rate the quality of the bids, and bidders can gain extra points if they restore certain features that were eliminated during an earlier round of cost-cutting, including canopies over the stations, elevators, public art, and a portion of a bike path along the tracks.

Green Line Constructors — which consists of Texas-based Fluor Enterprises, the Middlesex Corporation, and other companies — included all of these optional components.

The other finalist was another joint venture called Green Line Partners. A third group, Walsh-Barletta-Granite JV, was eliminated earlier this year, when it said it couldn’t complete the project under the $1.3 billion limit.

Construction will likely begin next year, with service expected to begin in 2021. Some early construction separate from this contract is already underway.

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The MBTA has estimated the entire project will cost $2.3 billion, and it will include new Green Line trolleys, real estate purchases, and other related contracts.

The Baker administration had put the project on hold two years ago after new estimates put the expected cost close to $3 billion. The state eventually fired the prior contractors and revised portions of the extension with more limited station designs and fewer amenities to get the cost to $2.3 billion.

The extension’s long and winding history dates back decades, and it is already well overdue by prior scheduling estimates. It is a legal requirement as environmental mitigation related to the Big Dig highway project.

The federal government will pay about $1 billion, with the state paying most of the rest. The cities of Somerville and Cambridge are also contributing, and expect to recoup some of that money from property owners whose land will increase in value because of proximity to the new service.

In the more distant future, the T may send service deeper further into Medford, to Route 16, as a further expansion of the project. But that project is separate from the first seven stations and is not currently funded. Instead, money that had been designated for the route to Route 16 was redirected to pay for the first part of the extension as its budget grew.

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