The Arizona Department of Transportation has identified three possible routes for a train connecting Tucson and Phoenix. This image shows the "green" alignment.

Three possible routes for a proposed rail line between Tucson and Phoenix have been identified by the Arizona Department of Transportation.

The state agency made the announcement this afternoon, with three possible routes being identified following a series of public meetings over the best way to serve the needs of the state’s two largest metropolitan areas.

The three proposals — identified by ADOT by the colors green, yellow and orange routes — offer different paths between the two areas. Two of the routes serve stops in the East Valley while the third largely follows Interstate 10. The southern half of the proposed rail lines are the same, sticking close to I-10 from Eloy to the southern portion of Tucson, ending at the airport.

ADOT officials expect to identify the final route by the end of the year.

Estimates for the final costs to design, build and maintain a rail line between Tucson and Phoenix could eventually cost taxpayers between $5 billion and $10 billion.

Funding for the proposal has yet to be determined, ADOT officials said on Tuesday.

Contact reporter Joe Ferguson at or 573-4346.

Senior Editor, News, Arizona Daily Star, Tucson, Az.