As used in this subchapter, unless the context otherwise requires, “private car company” means every person, company, or corporation other than a railroad company, engaged in the business of operating cars or engaged in the business of furnishing or leasing cars for the transportation of freight, property, or persons, whether or not the cars are owned by the person, company, or corporation, over any railway lines, in whole or in part within this state, whether the cars are termed box, coal, flat, furniture, gondola, ore, refrigerator, stock, tank, express, or sleeping car, or by some other name.