“Your project schedule is mechanically sound, but optimistic — any delays in your schedule would most likely result in additional costs to the project,” she wrote.

In a letter sent last week to Transportation Secretary Stephanie Pollack, FTA regional administrator Mary Beth Mello said the federal agency still needs a “good deal of clarifying information” before signing off on the project and handing over nearly $1 billion in federal funding.

The Federal Transit Administration remains “committed in principle” to funding the Green Line light rail extension into Medford and Somerville, but made clear it still has reservations about the MBTA’s embattled project, according to a letter obtained by the Globe.


The Green Line extension into Somerville and Medford was imperiled last year by dramatically increased cost estimates that threatened the entire project after the MBTA rushed through the work, designed expensive and elaborate stations, and failed to catch the rapidly rising costs.

The project is still in a state of limbo, even after the transportation boards overseeing the project voted in May to move forward with the 4.7-mile extension. The Department of Transportation’s board and the MBTA’s fiscal control board made clear that they could yank approval if the T can’t find more funding for the project, the FTA refuses to provide federal funds, or the agency can’t hire and train dozens of employees in a new contracting method to work on the extension.

The T significantly slimmed down aspects of the project, which earned an initial approval from the FTA. Now, MBTA officials are waiting for the FTA to fully approve the new version so that they can secure nearly $1 billion in federal funding.

In her letter, Mello said that the proposed scope is consistent with what the FTA had agreed to fund, and the cost estimates were complete, well-documented, and conservative. But she said federal officials did not have all the information needed for a complete view of the risks associated with the project.


Despite the reservations, Mello said the MBTA should continue moving forward by hiring a permanent managerial team, among other steps — but the T would need to use its own money, since the FTA cannot yet commit to contributing its own funding.

Joe Pesaturo, a T spokesman, said the state appreciated the FTA’s recognition of the agency’s work.

“Meanwhile, we will continue to remain focused on improvements to the core system and spending money to address the state of good repair backlog, long-term infrastructure needs, and winter resiliency upgrades,” he wrote in an e-mail.

Nicole Dungca can be reached at nicole.dungca@globe.com. Follow her on Twitter @ndungca.