Federal transit officials accept Green Line extension estimate

BOSTON (AP) — Federal transportation officials have signed on off on a new estimate for a long-awaited 4.5-mile extension to the MBTA's Green Line.

The Massachusetts Bay Transportation Authority said it received a report Monday from the Federal Transit Administration agreeing with the MBTA's $2.3 billion estimate for the extension.

The announcement helps move the project along and comes after the MBTA submitted a scaled-down redesign of the project which will extend the Green Line to Somerville and Medford.

The federal government had already pledged $1 million in grant money, but had to agree to the new cost estimate and schedule before the project could begin construction.

The $2.3 billion estimate is higher than the original estimate of $2 billion, but lower than subsequent projections that led to the decision of Republican Gov. Charlie Baker's administration to put the project on hold.

Last year, Somerville and Cambridge took the unusual step of offering $75 million to keep the project going. Somerville — which would enjoy the bulk of the extension — would kick in $50 million and Cambridge — which would get a new Lechmere Station — would contribute $25 million. The state will help close a final funding gap of $64.3 million through the use of special obligation bonds. Somerville Mayor Joseph Curtatone expressed support for the Federal Transit Administration decision. "My arm's getting tired from all these high fives," Curtatone tweeted Tuesday. State transportation officials said Tuesday they look forward to continuing to work with federal agencies to upgrade the public transit system that serves more than 1 million riders each day in the metropolitan Boston area. The project has proceeded along in fits and starts since 1990 when the state agreed to the extension as part of an environmental agreement that helped clear the way for Boston's massive Big Dig highway project. The project features 4.5 miles of aboveground light rail service, six new MBTA stations and the relocation of the existing Lechmere Station in Cambridge. The modified plan calls for the same number of new stations, but their design would be simplified to help lower costs.