The first parts of a proposal to design and build much of the extension of Metrorail to Dulles reached state transit officials on Monday, though the proposed cost of the massive transit project has yet to be unveiled.

Dulles Transit Partners, a group of firms made up of engineering giants Bechtel and Washington Group International, is expected to soon deliver a price tag on the first phase of the project, though it’s unclear exactly when. The first half of the 23-mile track would split off from the Orange Line after the East Falls Church Metro station and run to Wiehle Avenue.