These B-70-7 class 50’ insulated plug-door boxcars with Roller Bearing trucks were built in 1962 and rebuilt and renumbered by Cotton Belt in 1979. They featured a cushioned underframe, insulated walls, and CAR-PAC loaders. St. Louis Southwestern, commonly known as Cotton Belt, was founded in 1891 and became a Southern Pacific subsidiary in 1932, before eventually fully merging in 1992. It is now a heritage component of Union Pacific.
