An open-top, extremely sturdy railway car with sides and ends designed to transport iron and steel scrap, steel ingots, coiled steel, sheet steel, pipes, and other steel products. Aggregate gondolas are designed to transport industrial minerals, crushed rock, and gravel. Mill gondolas are designed primarily for the steel industry. Options include cross bars, load restraining devices, and wooden troughs for handling specialty cargo. Aggregate gondolas typically lack internal bracing in order to facilitate top unloading.