When any common carrier has put in force any rates, rules, or practices in relation to interstate freight business, in violation of the laws of the United States regulating commerce, or of the orders, rules, or regulations of the surface transportation board, or shall unjustly discriminate against any of the citizens, industries, interests, or localities of the state, the department shall present the material facts involved in such violations or discrimination to the surface transportation board and seek relief therefrom, and, if deemed necessary or expedient, the department shall prosecute any charge growing out of such violation or discrimination, at the expense of the state, before the surface transportation board.