S.C. Code § 30-11-10
All deeds of conveyance of railroad beds, tracks and rights of way, cars, locomotive engines, rolling stock and other railway equipment, all leases and conditional sales of, and all other instruments in writing relating to, such property in this State, other than mortgages and deeds of trust, delivered or executed on or after January 1 1894 shall be valid, so as to affect from the time of such delivery or execution the rights of subsequent creditors or purchasers for valuable consideration without notice, only when filed in duplicate within forty days from the execution and delivery thereof in the office of the Secretary of State. But the above-mentioned deeds, leases, mortgages and other conditional sales and instruments in writing, if filed subsequent to the expiration of such period of forty days, shall be valid to affect the rights of subsequent creditors and purchasers for valuable consideration without notice from the date of such record only, one of the copies of any such instrument so filed shall be given its proper file number, indexed and retained in the office of the Secretary of State and the other shall be properly endorsed, giving the file number under which it is to be found and returned.
S.C. Code § 30-11-10