The MidSouth Rail Corporation is a shortline running between Shreveport, LA and Meridian, MS. It used to be an independent railroad, but was purchased by the KCS in 1993, then converted to the jointly owned (with NS) Meridian Speedway in 2005.
When it was an independent railroad, it had a mess of branches and secondary lines, but KCS sold everything off except the Shreveport to Meridian line, which serves as a link between the KCS and NS.
Before the purchase, MSRC had a small fleet of EMD GP9s, GP18s, and CF7s, but they have been sold off and all freight is handled with KCS and NS/UP power.