Feds Approve Revised Cost Estimate For Green Line Extension

The long-stalled MBTA Green Line Extension gained momentum Tuesday.

The Federal Transit Administration announced it's approved a scaled-back cost estimate for the planned expansion of service into Somerville and Medford.

The project was put on hold in August 2015 after a revised cost estimate ballooned from about $2 billion to $3 billion.

In 2016, state transportation leaders scaled back the project's plans, resulting in a new cost estimate of $2.3 billion. Federal regulators had to OK that modified proposal, unlocking crucial federal funds.

"It's kind of the culmination of a lengthy process of reevaluating the project's scope and making sure the ultimate product is consistent with the funds we have available and the time-frame we have to do it," said John Dalton, the project's manager.

Dalton says the next step is to finalize design plans and then begin construction.

The 4.5-mile extension includes the development of six new stations, as well as the relocation of Lechmere Station in East Cambridge. It's set to open in 2021.