While the MBTA investigated a runaway train on the Red Line Thursday, the runaway costs of the proposed Green Line extension had the full attention of the T's fiscal guardians.

The MBTA announced Thursday that it will seek to terminate the contracts for the ongoing construction on the rail extension that would bring the Green Line from a relocated Lechmere Station through Somerville and into Medford.

The move to ditch the contracts so soon after the board met to discuss the issue, just Wednesday, shows that the agency is serious about doing something about the gaping budget hole that's growing at a pace much faster than, well, the pace the Green Line travels.

The T informed several firms working on the project, including the project's general contractor, White Skanska Kiewit, that the agency will end current construction arrangements.

Starting the contracts over from scratch is the first step in a process that will end with either the project being canceled outright or being scaled back to be affordable.

Gov. Charlie Baker's hand-picked Fiscal Control Board and the MassDOT Board met Wednesday to discuss options to salvage the project and to hear from the public.

The board went over the options for how to deal with the massively over budget project. The panel discussed scenarios at the public meeting involving drastically altering the design, scope and contracting process for the system in order to meet a more modest budget.

The project's price tag was set at around $1.9 billion as of December 2014, with federal dollars picking up $1 billion. That number went out the window this summer, when new construction estimates from the general contractor suggested the cost of completing work would be closer to $2.7 billion or $3 billion.

"I think a lot of people in Massachusetts would question whether or not, in fact, we should spend $3 billion on four miles. It's not even below ground. There's something about this that's not right," Baker told WGBH's Boston Public Radio in September, a sure sign that the Republican governor is willing to strike out the trolley line if the funding numbers can't meet his stands of fiscal responsibility.

The agency also announced that it will restructure the project management team behind the extension and will appoint a new interim project manager. That means heads could be about to roll over allowing the project's estimates to get so out of hand.