These 3-bay covered hoppers were built by American Car & Foundry in 1979 for Golden West Service, and later acquired by SSW, before being painted UP grey in 2014. 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.
This 3-pack is not part of any standing order.