The famous and popular California Zephyr was jointly operated by CB&Q, D&RGW, and Western Pacific. On May 1, 1971 the CZ died; but, the Rio Grande continued to operate its portion of the former CZ route between Denver and Salt Lake City as the Rio Grande Zephyr. The train continued to operate independent of Amtrak until 1983. During those 12 years, it operated the train with an F9 ABB engine (with a steam generator unit in winter) consist pulling a combination baggage car, four domes, dining car, no slumber coaches, and the, famous dome observation car.
Here's a sampling of views of the train:
The F9A #5771 and the F9B's pictured were customarily the only motive power for the RGZ's tri-weekly service each way with no train service on Wednesday.