i don't know what era you are modeling, which would really help. So I tried to give a broad guide for the 1920-1960 era below.
This is the roster for D&RGW gondolas used in coal in the 1930-1960 time frame, not including later renumbers in the 1950s, derived from data provided by Jim Eager. Other than Corey Bonsall and W&R, none of these cars are directly offered in an accurate model in HO. The 46000-46499 50-ton cars have a close match in the Red Caboose GS gon (absent the Duryea underframe). The problem is the 46000-46499 cars weren’t much used in coal service because they were 50-ton cars in a Western Territory rate structure that wanted 70-ton cars by the time they were manufactured in 1948. They were more often used for sugar beets, round wood, ties, and other low-density commodities.
D&RGW coal was as much as 50 percent loaded in box cars in the winter months, and approximately 25 percent loaded in box cars in the summer months. Generally the high-value lump sizes used for domestic heating were loaded in boxcars, and the mine-run and crushed sizes used for industrial fuel, coking, and railroad fuel were loaded in gons. Box cars used for coal were anything 36’ long or 40’ long that could be obtained, except usually not automobile box cars. Foreign road box cars were very common in coal traffic, more so than home-road cars. Stock cars were also frequently used for large lump sizes, with foreign road cars very common.
Union Pacific and Utah Coal Route GS gons were not uncommon to see in Utah, but generally the Utah Coal Route didn’t filter into D&RGW service, probably because the Utah Railway griped strenuously when that happened. GN and WP gons showed up on occasion. I’ve never seen a photograph of an SP GS gon on D&RGW in coal traffic service. MoPac hoppers were not uncommon to see in Colorado, along with C&EI and Southern. Burlington, C&S, and Santa Fe gons and hoppers appear in photos in the pre-WWI years, but very rarely after WWI. D&SL gons wandered off into D&RGW service; I’ve seen photos of them at Pueblo. I’ve also seen photographs of Colorado Midland gons at Pueblo, before that road shut down. I’ve seen a few photos showing NYC, PRR, B&O, and N&W hoppers in the 1930-1965 time frame, but these are NOT common. Carbon Country Railway hoppers rarely ran east of Utah, but there’s one photograph showing three of them at Salida, circa 1965. – Mark Hemphill
40000-41000 – 36’0” IL, 50-ton, 1400 cf, PSC 1908, all steel, inside stakes sides, 10” wood side extensions applied by D&RGW
41001-42500 – 36’0” IL, 50-ton, 1400 cf, PSC 1908, all steel, inside stakes sides, 10” wood side extensions applied by D&RGW
43000-43349 – 40’0” IL, 50-ton, 1750 cf, PSC 1912, all steel, inside stakes sides
43350-43629 – 40’0” IL, 50-ton, 1658 cf, WSCF 1913, all steel, inside stakes sides, ex-D&SL 34001-34300, renumbered/relettered beginning 1947
45000-45499 – 42’0” IL, 55-ton, 2100 cf, PSC 1926, all steel, inside stakes sides
46000-46499 – 42’9” IL, 50-ton, 2100 cf, PSC, 1948, all steel, 7-rib riveted sides, ID 4 ends, Duryea underframe
46500-46999 – 42’9” IL, 50-ton, 2100 cf, PSC, 1948, all steel, 7-rib riveted sides, AAR 4 ends, Duryea underframe
47000-47499 – 42’9” IL, 50-ton, 2100 cf, PSC, 1949, all steel, 7-rib riveted sides, AAR 4 ends
70000-70699 – 46’3” IL, 70-ton, 2400 cf, WSCF 1922, all steel, inside stakes, some had coke racks applied by D&RGW
71000-71779 – 46’0” IL, 70-ton, 2340 cf, PSC 1943, steel UF, 7-rib composite sides, AAR 5 ends, Duryea UF, rebuilt with steel sides beginning 1949
71780-71999 – 46’0” IL, 70-ton, 2340 cf, PSC 1943, steel UF, 7-rib composite sides, AAR 5 ends, Duryea UF, rebuilt with steel sides beginning 1949
72000-73699 – 46’0” IL, 70-ton, 2410 cf, GATC 1953, all steel, 7 rib riveted sides, ID 5 ends
ID = Improved Dreadnaught Ends
IL = Inside Length
cf = cubic feet capacity
UF = underframe
GATC = General American Transportation Corp.
PSC = Pressed Steel CarWSCF = Western Steel Car & Foundry