Alabama Department of Revenue v. CSX Transportation, Inc., 575 U.S. ___ (2015), was a United States Supreme Court case in which the Court held that "the Eleventh Circuit properly concluded that CSX's competitorsare an appropriate comparison class for the Railroad Revitalization and Regulation Reform Act of 1976's subsection (b)(4) claim." The Act prohibits states from imposing "another tax that discriminates against a rail carrier" and the Court found that the Eleventh Circuit "erred in refusing to consider whether Alabama could justify its decision to exempt motor carriers from its sales and use taxes through its decision to subject motor carriers to a fuel excise tax."