research info needed on C&S 638 trip

Have some C&S film, and we have one trip we cannot figure out the date, nor the destination. I will describe what we have and perhaps someone might offer a possible destination.
The trip was run from Denver Union Station with C&S 638. It had one green baggage car, and 4 silver cars(2 were clerestory roof Burlington cars I think), plus a green business car #69 on the rear.
It had an Intermountain Chapter NRHS drumhead on the rear(car 69). The train did at least two runbys at one location, which looked like an open area perhaps in a town.
After that we see the 638 run around the train on a siding, and couple pilot to the end of the train, as if it were going to run tender first. Then the segment ends.
Sorry this isn't narrow guage but being C&S is somewhat related.
Greg Scholl