§ 77. Equipment of engines. It shall be unlawful for any railroad company to use within the state on its line or lines any locomotive engine not equipped with a power driving wheel brake and appliances for operating the train brake system, or to use any locomotive engine operated by steam not equipped with a mechanically operated door to the fire box of such locomotive engine, or to use any locomotive engine not equipped with a vestibuled cab. Such mechanically operated door shall be so constructed and operated by steam, compressed air, electricity or other means, and such vestibuled cab shall be so constructed as deemed best and most efficient by the officers of such railroad. The device for operating such door shall be so constructed that it may be operated by the fireman on said engine by means of a push button or other appliance located in or near the floor of the deck or floor of the tender at a suitable distance from such door to enable the fireman while firing such engine, by pressure with his foot to open such door for the firing of such engine, and such vestibuled cabs shall be so constructed as to attach to the sides of, and enclose all openings between the engine cab and the water tank or coal tender attached to such engine; provided, however, that nothing in this section shall be construed to inhibit the passage of a locomotive engine not so equipped with such mechanically operated door or vestibuled cab, moving under its own steam either with or without a train, when such movement is from a point without this state through and to a point beyond its borders, or from a point without this state to a point within it, or from a point within this state to a point without it if such passage is for the purpose of moving it to or from a repair shop or shops for the purpose of repairing such locomotive engine, and when it is not intended for service within this state.