These rib side twin bay open hoppers are painted SP Brown with white logo and lettering. They were built in October 1956 by American Car & Foundry and run on Bettendorf trucks. Built from an order of 275 cars on Lot #01-4705, these hoppers were built as SP series 460557-460681 and as SP subsidiary Texas & New Orleans as T&NO series 41150-41299. This series of hoppers is designated AAR class HK and is used for ballast service.