Boxcars were the category of freight cars the most important in number on the Rio Grande narrow gauge roster, nearly 4,000 boxcars were built for the railroad all together. They were used to transport any kind of cargo, from ore to manufactured goods. The first D&RG boxcars, built in 1871 according to a Billmeyer & Small pattern, were 10 short and light (12ft long and with a capacity of 10 tons) 4-wheel cars, all retired from service before 1883. These cars were considered too light and in 1872 and 1874, 166 new 8-wheel boxcars with a 8-ton capacity were built by the Denver & Rio Grande, still with parts and according to plans from Billmeyer & Small. They have been used until 1903. Then in 1879, the St. Charles Car Company built another 50 10-ton capacity boxcars for the D&RG, they were all scrapped before the end of 1906. Between 1878 and 1883, the Rio Grande shops built the railroad largest class of boxcars: over 2500 cars with a capacity of 10 tons and a length of 24ft. In 1903, some of these cars (those being in the best shape) were rebuilt with new trucks increasing their capacity to 20 tons, and with automatic couplers and air brake to comply with the new Interstate Commerce Commission regulations. Another hundred boxcars from the same class have been more heavily modified between 1884 and 1895 with new 20-ton trucks and a length increased to 27ft. These boxcars were also rebuilt in 1902 to meet the new Interstate Commerce Commission standards and were renumbered between 4000 and 4099. In 1923, only a few of these boxcars remained on the Rio Grande roster, most of them as company cars in the MOW fleet. A boxcar of this class, sold to the Rio Grande Southern in 1891 and converted later to a bunk car as #01789, is preserved today at the Colorado Railroad Museum.
In 1895 and 1896, the Denver & Rio Grande ordered two series of 200 boxcars from the Ohio Falls Car Manufacturing Company, with a capacity of 20 tons and 30ft long. In 1902 half of them were renumbered in the 4400-4499 and 4900-4999 blocks, the remaining ones took available numbers in the 4000 block and higher. A dozen of these cars were converted in 1916-17 to carry automobiles by adding large doors at one end. In 1923, over 200 of these boxcars remained on the Rio Grande revenue roster and a hundred other had become non-revenue work boxcars, after modifications for some of them. Several boxcars of this class have survived today in their non-revenue service version, most of them in the Cumbres & Toltec Scenic Railroad collection of MOW equipment, such as #04444. In 1942, all the boxcars of this class still in revenue service were transfered to the US Navy at Pearl Harbor. Fifty other 20-ton 30ft long boxcars have been built for the D&RG in 1902 and numbered from 4500 to 4549. The last of the class (#4549), which became tool car #04549 in the Rio Grande non-revenue fleet, is preserved today on the Cumbres & Toltec Scenic Railroad. One last class of 750 boxcars, 30ft long and with a capacity of 25 tons, has been delivered to the D&RG by the American Car & Foundry in 1904, they were numbered from 3000 to 3749. In 1926, these boxcars were extensively rebuilt, keeping only a few iron parts from the original boxcars, but the new cars retained the same numbers. A large part of these boxcars remained in revenue service until the end of freight operations on the Rio Grande narrow gauge in 1968. Many boxcars of this class have been preserved today, including 45 on the Durango & Silverton Narrow Gauge Railroad, about twenty in their original condititon on the Cumbres & Toltec Scenic Railroad (plus 22 other converted to passenger cars), 9 at the Georgetown Loop Railroad and another 4 at the Colorado Railroad Museum. All the Rio Grande boxcars were completely made of wood (body and frame), except for numbers 3000-3749 which received a steel roof during their 1926 rebuilding.
D&RGW boxcar #3705 preserved at the Colorado Railroad Museum. This lettering scheme was in use between 1921 and 1926.
Work boxcar (block car) #04444, carrying wood blocks used during wreck clean-up operations. It was originally D&RG boxcar #4444 built in 1895.
Rio Grande boxcar #3669 in a livery used after 1939, conserved in working order on the Cumbres & Toltec Scenic Railroad.
Boxcar #3407 at the Georgetown Loop Railroad, freshly painted in the livery used by the D&RGW between 1936 and 1939.
B end of boxcar #3705, with its hand brake.
D&RGW boxcar #3275 today in use on the Durango & Silverton Narrow Gauge Railroad (D&SNG).
Line-up of boxcars in the Chama yard on the Cumbres & Toltec Scenic Railroad.
Boxcar #3134 in Rio Grande gold livery. It is used today as a baggage car on the Durango & Silverton Narrow Gauge Railroad.