Any non-perishable product. Limited use for livestock since the shipment would need to be discontinuous (livestock fed/ and allowed to graze and rest) unless being used for butchering at other end of line. This method was used to transport racehorses in 1930's over large distances (transcontinental races). See the movie "SeaBiscuit" for a reference.
Agriculture and Industrial products. Agricultural products could now be moved from the West to industrialized cities in the East. Industrialized cities could now ship their products(like textiles, machinery,and hardware) to the West.