Boston — The MBTA is seeking letters of interest from firms that may want to provide services for the Green Line Extension (GLX) project. This step initiates the process for engaging potential bidders in the design and construction industry in the next phase of the project.

The MBTA will host a forum on November 16 in the state transportation building to discuss the current scope of the GLX project, and anticipates inviting firms capable of leading design-build teams to accomplish the work.

The project includes the design and construction of two distinct branches that will serve as an extension to the Green Line: a “mainline” branch which will operate within the existing right-of-way of the Lowell Line, beginning just south of a relocated Lechmere Station in Cambridge and traveling north to Medford, and a branch line operating within the existing right-of-way of the Fitchburg Line to Union Square in Somerville. There will be seven new stations constructed as part of the project, including the relocated Lechmere Station, as well as associated electrical and signal systems. A vehicle storage and maintenance facility will also be constructed.

To date, the GLX project has reached a number of important milestones.

On August 8, the MBTA’s Fiscal and Management Control Board authorized the MBTA to proceed with the next phase of the Green Line Extension project: the development of procurement documents for the ultimate selection of a new construction team.

A Memorandum of Understanding between MassDOT and the City of Cambridge for the city to contribute $25 million to fund elements of the Green Line Extension project within the city of Cambridge (particularly costs associated with the relocation and reconstruction of Lechmere Station). Both the FMCB and the MassDOT board voted to accept the memorandum of understanding with the city of Cambridge, accepting the city’s funds. The $25 million contribution will be transferred from the City of Cambridge to the Commonwealth, over the course of several years.

MassDOT is working with the City of Somerville to advance a similar MOU to account for the pledged $50 million contribution from Somerville.

A comprehensive review of the project to identify cost reductions and steps to streamline and improve the planning and construction process.

Continued close-out of existing construction contracts.

The project still hinges on the release of $1 billion in funds pledged by the federal government. The Federal Transit Administration (FTA) earlier this year expressed support for the work performed to date by the Interim Project Management Team. In a letter to MassDOT Secretary Stephanie Pollack, FTA Regional Administrator Mary Beth Mello wrote the “IPMT has made every effort to redesign the project in ways that preserve its most essential transportation benefits, consistent with your fiscal constraints.”

The FTA calls the MBTA’s cost estimates “complete, well documented,” the project scope “consistent with the scope of work set forth in the Full Funding Grant Agreement”, and the project schedule “mechanically sound.”