Colorado Railroad Museum, Golden, Colorado.
(Railfan jargon - "Covered Wagon" = an EMD E-series or F-series locomotive)
D&RGW 5771 & 5762
Builder's No. 20527 (F9A) and 20531 (F9B) used in multiple with other A and B units in mainline freight service between Denver and Salt Lake City and also used on the California Zephyr in the 1960s and the Rio Grande Zephyr in the 1970s and early 1980s. Last revenue trip in freight service September 30, 1984; donated by the Southern Pacific Lines 9/11/96.
EMD F-units were a line of Diesel-electric locomotives produced between November 1939 and November 1960 by General Motors Electro-Motive Division. Final assembly for all F-units was at the GM-EMD plant at La Grange, Illinois. They were sold to railroads throughout the United States, Canada and Mexico. The term F-unit refers to the model numbers given to each successive type, all of which began with F.
F-units were originally designed for freight service, although some hauled passenger trains. Almost all F-units were B-B locomotives; they ran on two Blomberg B two-axle trucks with all axles powered. The prime mover in F-units was a sixteen cylinder EMD 567 series mechanically aspirated two-stroke Diesel engine, progressing from model 16-567 through 16-567C.
Structurally, the locomotive was a carbody unit with the body as the main load-bearing structure, of a bridge-truss like design, and covered with cosmetic panels. The so-called bulldog nose was a distinguishing feature of the locomotive's appearance, and made a lasting impression in the mind of the traveling public.
The F-units were the most successful "first generation" road Diesel locomotives in North America, and were largely responsible for the replacing of the steam locomotive in road freight service.
F-units were sometimes known as covered wagons, due to the similarity in appearance of the roof of an F-unit to the canvas roof of a Conestoga wagon, an animal-drawn wagon used in the westward expansion of the United States during the late 1700s and 1800s. When a train's locomotive consist included only F-units, the train would then be called a wagon train. These two usages are still popular with the railfan community. (Wikipedia)