A reader corresponded with TDOT regarding the need to at least plan for future passenger rail service between the airport and Knoxville, noting that there are tracks across the highway that go all the way to the Worlds Fair site in downtown Knoxville.

The problem is that the proposed improvements do not allow for the tracks to be extended to the airport side of the highway, so the suggestion is to at least include a tunnel or underpass for future use if a new Hunt Rd. interchange is built.

TDOT responds to the query:

As you may already know, there are others in the greater Knoxville area who are also interested in the potential use of the track between Alcoa and Knoxville. From what I understand, there is still some freight rail traffic on this track, but not enough to preclude consideration of its future use for commuters.

TDOT recently provided funds to the Knoxville Area Transportation Planning Organization (TPO) to undertake a review of various regional corridors and then recommend those with near-term transit potential, so that more focused design efforts can begin. This corridor will very likely be evaluated. I am therefore copying Jeff Welch, the TPO's director, to make him aware of your interest.

I am also sharing your suggestion about incorporating an underpass with the TDOT project manager for the Alcoa Highway project, Mike Russell. [..] He will be better informed as to the project development schedule and our ability to consider the proposal at this stage.

The reader also notes that the $500 million Kinsey-Probasco plan for the new Downtown Alcoa development includes "future light rail service access between downtown Knoxville and the airport."