In any contract for the leasing or hiring of railroad or street railway equipment or rolling stock, it is lawful to stipulate for a conditioned sale thereof at the termination of the contract, and that the rentals or amounts to be received under the contract may, as paid, be applied and treated as purchase money, and that the title to the property shall not vest in the lessee or bailee until the purchase price has been paid in full and until the terms of the contract have been fully performed, notwithstanding delivery to and possession by the lessee or bailee.