Today the U.S. Court of Appeals for the Sixth Circuit remanded a dispute concerning the district court’s denial of preliminary-injunctive relief to five major railroad companies that individually brought suit against the Tennessee Department of Revenue in response to the recently enacted Tennessee Transportation Fuel Equity Act, which the railroad companies contend violates the federal Railroad Revitalization and Regulatory Reform Act of 1976 (4-R Act).  The 4-R Act prohibits states from imposing taxes that discriminate against a rail carrier.