(a) Every contract authorized by Code Sections 46-8-270 and 46-8-271 shall be good, valid, and effectual to retain the title to the property in the vendor or lessor, or in his assigns, as against the vendee or lessee and as against all persons claiming under the lessee.

(b) Such contracts, if made within this state, shall be executed in the presence of, and attested by or proved before, a notary public, a judge of any court in this state, or a clerk of the superior court. If such a contract is made outside this state, it shall be executed in the presence of, and attested by or proved before, a commissioner of deeds for the State of Georgia, a notary public having authority to act as such in the state or other jurisdiction within the United States where the contract is made, a consul or vice-consul of the United States (the certificates of the foregoing officers, under their seals, being evidence of the fact), or a judge of a court of record in the state where executed. Within six months after the date of its execution, any such contract made outside this state shall be executed in the office of the clerk of the superior court of the county where the principal office in this state of the railroad company is situated.

(c) Each locomotive engine and each car so sold or leased or contracted to be sold or leased shall have the name of the vendor or lessor, or the assignee of such vendor or lessor, plainly placed or marked on the same; or it shall be otherwise marked so as to indicate plainly the ownership thereof.