Nothing contained in this act shall be construed as applying to the military or naval forces of the United States or its allies, or the duly authorized militia of any State, nor to the police or fire departments of this State, providing the same are acting in their official capacity and in the performance of their public duties.
A. Nothing contained in this act shall be construed as applying to explosives which are in transit upon vessels, railroad cars or vehicles or while being held for delivery, when such transportation and delivery are under the jurisdiction of and in conformity with regulations adopted by the Interstate Commerce Commission, the United States Coast Guard or the Civil Aeronautics Board, and provided, further, that nothing in this act shall be construed as applying to the receipt, possession, and use of signals required for the safe operation of vessels, motor vehicles, railroad cars, or aircraft by the operators of such vessels, motor vehicles, railroad cars or aircraft.