The Chesapeake & Ohio had ordered six dome cars for its ill-fated Chessie train, including three dome-sleepers and three dome observation cars. When the B&O purchased the dome-sleepers for its Capital Limited, the other three went to the Denver & Rio Grande Western. The Rio Grande apparently did not want observation cars (which require extra switching to turn them around at each end of a trip) and so it converted them for mid-train operation.
One of the Chessie dome-observation cars converted for mid-train use on the Royal Gorge. Note that the car next to it is a heavyweight car.
Starting in September, 1949, the Rio Grande added these cars to its Royal Gorge train, which connected Denver and Salt Lake City via Pueblo and Tennessee Pass–a longer route than the one followed by the California Zephyr. The Royal Gorge merged with the Prospector, which followed the same Denver-Salt Lake route as the Cal Zephyr on an overnight instead of a daytime schedule, in Grand Junction, so the Prospector too could say it was a dome-car train for at least part of its route. Since the Rio Grande had three of these domes, and only needed two for the Royal Gorge at any given time, it is likely that domes sometimes ventured east of Grand Junction on the Prospector trains.
Click image to download a 2.8-MB PDF of this brochure about Rio Grande vista-dome trains.
In advertising the fact that the Rio Grande offered dome cars on four different trains–the California Zephyr, Royal Gorge, Prospector, and Colorado Eagle–the above brochure takes a few liberties. First, although the Prospector and Royal Gorge domes were the same cars, the pictures show one named “David Moffat” and the other numbered “1248.” In fact, as near as I can tell, none of the Chessie-type domes were ever named when in Rio Grande service. The diagrams also show standard dome cars instead of observation cars converted for mid-train service. At least the pictures correctly show the forward-leaning posts on the lower row of dome windows.
Another quirk of the brochure is that is shows the Colorado Eagle dome with the name “Arkansas River.” As far as I can tell, however, Missouri Pacific (which owned and operated the Colorado Eagle from St. Louis to Colorado Springs; the Rio Grande only ran it from Colorado Springs to Denver) didn’t name its domes.