All interurban railroads operating within this State shall furnish their cars, and the vestibule portions of their cars, for the carriage of passengers with heating apparatus or appliances necessary to the comfort of all passengers and operators using them. But this section shall not apply to any railway whose direct line is more than fifty miles long. Any interurban railroad failing or refusing to comply with the provisions of this section shall be subject to a fine not exceeding one hundred dollars for each day of such failure or refusal, to be recovered in any court of competent jurisdiction. Such fine shall be paid into the county treasury of the county in which the action or suit is brought, to be applied to the public school fund of such county. The term "interurban railroads" as used in this section shall have the same meaning as is provided in § 58-21-260.