For the inaugural trip in 1941, the railroad made stainless steel pass holders that were intended to be distributed to passengers.

New, diesel power, stainless steel streamlined train designed for overnight every night service between Denver and Salt Lake City.

[citation needed] The trainsets had significant reliability problems exacerbated by difficult terrain and the train was discontinued July 5, 1942.

Anticipating increases in overnight Denver-Salt Lake City rail passenger traffic after the end of World War II, the Rio Grande restored the Prospector on October 1, 1945, using conventional heavyweight equipment.

Between 1964 and 1967 the railroad occasionally attached flatcars carrying highway vans —piggyback cars — to the rear of the Prospector, a relatively rare combination of passenger and freight service in the same train.