Regional Authorities and Special Districts - As enacted, makes changes to the law relative to the South Central Tennessee Railroad Authority, including establishing that three or more of the counties of Dickson, Hickman, Lewis, Perry, and Wayne and the cities of Dickson, Centerville, and Hohenwald are authorized by a vote of two-thirds of their respective governing bodies to become members of the authority. - Amends TCA Title 4 and Title 64, Chapter 2, Part 2.