S.C. Code Ann. § 58-17-2730

No railroad doing business in this State shall be allowed to refuse to issue or recognize a through bill of lading between competitive points when issued over or by one railroad with which it connects when it issues or recognizes such bills of lading when goods are shipped to or from such points over any other competitive railroad with which it connects reaching such point. Such railroad shall not charge or receive for such goods passing over its lines, either by the appropriate schedule for local freight or a division of a through freight rate, a greater sum when such goods are shipped by or over one line of railroad with which it connects than it would charge or receive when such goods are shipped by or over any other line of railroad with which it connects. But nothing herein contained shall prevent any such railroad from demanding payment of its charges in advance of performing the service of carrying such goods or from limiting its liability to losses or damage to such freight upon its own line by a clause inserted in the bill of lading.