THE GREEN LINE EXTENSION moved closer to reality on Tuesday, as the Federal Transit Administration said it agreed with the MBTA’s $2.289 billion cost estimate for the project and state officials came up with an extra $64 million to close the funding gap.

The Federal Transit Administration has been reviewing the T’s new cost estimate for the redesigned project for several months and this week said it concurred with the transit agency’s analysis. The FTA originally awarded $996 million in funds for the Green Line Extension, but the project and the funding were both put on hold when the cost ballooned to more than $3 billion. The project was then redesigned to reduce the cost to $2.289 billion, and state officials have been waiting for the federal agency to give the green light to proceed.

The FTA’s concurrence with the MBTA’s cost estimates isn’t the final step before the federal funds can be released for the project, but it’s pretty close.

“It’s a very positive step, but I can’t write a check,” said John Dalton, the manager of the Green Line Extension. He said the T still needs federal approval of the state’s finance plan for the project.

As it stands now, the T is counting on $996 million from the FTA, $996 million from the state, $157 million from highway fund originally directed to the Boston Metropolitan Planning Organization, $50 million from Somerville, and $25 million from Cambridge. The remaining $64 million hole is being plugged with state bond money and unused contingency funds from other projects.

T officials said $32 million of the $64 million will come from special obligation bonds issued under the state’s Rail Enhancement Program. Of the remaining $32.3 million, $4 million will come from left-over contingency funds from a completed T garage in Salem and a Wachusett extension project on the Fitchburg commuter rail line, and $28.3 million from a contingency fund set aside for Red and Orange Line infrastructure.