The manufacturer, owner, or assigns of any railroad equipment or rolling stock may make a written contract for the lease of such equipment or rolling stock to any company owning or operating a railroad in this state. In such contract, it shall be lawful to agree to a conditional sale of the property to the lessee on the termination of the lease and to stipulate that the rental received for said property may, as paid or when fully paid, be applied to and treated as purchase money. Any such agreement for a conditional sale may contain such terms as to the time of passage of title as are authorized by Code Section 46-8-270.