No member of a train crew, yard crew or engine crew of a railroad which is a common carrier shall be held criminally responsible or found guilty of violating any state laws or of any municipal ordinances regulating or intended to regulate the blocking of any street, road or highway grade crossings by trains or passenger or freight cars upon reasonable proof that the blocking of said street, road or highway grade crossings was necessary to comply with the orders or instructions, either written or oral, of his employer or its officers or supervisory officials; provided, however, that the provisions of this section shall not relieve the employer or railroad from any responsibility placed upon said employee or railroad by any such state laws or by such municipal ordinances; and provided further, that the employer or railroad shall stand in the place of the member of the train crew, yard crew or engine crew in such circumstances and shall be responsible for the violation of any such state laws or municipal ordinances and any criminal fines resulting therefrom.
The provisions of this section shall be enforced by the Mississippi Department of Transportation.