An industry standard since the 1930s, the 3-bay hopper was adopted as an AAR recommended design. Although offering greater carrying capacity than flat-sided cars, the joints were easily damaged by sulfuric acid (created by wet coal), and the cars fell out of favor by the mid-1950s as repair costs mounted.
 
Cars feature: * True scale dimensions with accurate details * Weighted, detailed underframes * Equipped with AccuMate(R) Knuckle Couplers * Trucks equipped with free-rolling metal wheels * Accurate painting and lettering