Did the Burlington have diesels by the time the Alamosa Train was taken off?
By 1953 EVERY big Class 1 (except the N&W) had diesels - nearly 90% of freight ton-miles was diesel-hauled. And CB&Q was one of the earliest adopters of non-steam power (the "Zephyrs").
What Jerry Says about the prospector is possible as well. . . Not sure how different the Prospector looked from the "Royal Gorge" train at this time.
The "Prospector" ran Denver - Moffat - Grand Junction - Ogden, beginning in 1946. It was initially equipped with Pullman-Standard streamline stock originally intended for the "Chessie" turbine-hauled train. In 1950 the "Prospector" and the "Royal Gorge" were combined west of Grand Junction. If you've got a shot of 5484 near Pueblo, it's not hauling the "Prospector" - it's hauling the "Royal Gorge."
After early 1951 (the Alamosa train was on a day schedule that connected with the "Royal Gorge" by March, implying that the overnight 15/16 on the main line was gone), only 1/2 (Denver - Ogden) and 15/16 (day Pueblo - Alamosa) served Pueblo on the D&RGW.
If I am right on my guess, that the platform side of the Pueblo Depot faced east, then these shots were made in the morning. . . . For what it is worth I noted another coach sitting on the same track as this steam passenger train, so it could be an "overflow" car
This photo is of westbound train no. 1. Platforms are on the southwest side.
The car looks like a Pullman, and may be the through car to or from St. Louis via the MP. (The WP, D&RGW, and MP all operated connecting trains called the "Royal Gorge" - in fact, MP used "Royal Gorge" as the name of its St. Louis - Pueblo - Denver train before D&RGW used the name.)
Pueblo Union Depot would have been a busy place around lunchtime - no. 16 arriving from Alamosa, 1 and 2 meeting, and no. 15 departing. I assume MP's "Royal Gorge" passed through not long before the D&RGW arrived, to minimize the layover.
A couple of MP's "Royal Gorge," which based on these photos arrived Pueblo late morning:
JAC