Nothing in this article or in Article 6 (commencing with Section 851) requires a common carrier by railroad subject to the Interstate Commerce Act (49 U.S.C. Sec. 10101 et seq.) or passenger stage corporation to secure from the commission authority to execute any conditional sales contract for the purchase of motor vehicle or railroad equipment or any note or chattel mortgage on that equipment securing the payment of all, or any part, of the purchase price.