Section 78-A - Electric or battery-powered markers1. Any railroad using a passenger, mail, work, or wreck train shall equip the last car of each such train with electric markers of sufficient candle power to be visible for a distance of three thousand feet under normal weather conditions. Battery-powered, flashing-type, or constant burning markers shall be deemed sufficient compliance with the foregoing requirement.2. If, in any particular case, exemption from any of the requirements herein is deemed necessary by the railroad concerned, the commissioner of transportation may grant the application of such railroad, for such exemption when accompanied by a petition setting forth the conditions existing and the reason why such exemption is asked. Any exemption so granted shall be limited to the particular case covered by the petition.