Auto, truck and trailer sales, service, storage and repair, provided, however, that dismantled or junked cars, or parts of cars unfit for operation on the highway shall not be stored or sold on the premises. Automobile service stations, provided all gasoline pumps or appliances for dispensing gasoline shall be located not less than 30 feet from the street right-of-way, nor shall a service station be erected or located closer than 2,000 feet from any other service station as measured along the street line.