These 2971 cubic foot capacity two-bay ACF hopper cars with Barber Roller Bearing trucks were built in 1974 for Denver & Rio Grande Western and belonged to series 10000-10069. After subsequent mergers in the 1990s, they were transferred to Union Pacific where they continue to serve today, repainted but still carrying the D&RGW reporting marks and series numbers. These cars were used to transport high-density granular commodities such as sand.