Both Union Pacific and Southern Pacific had PR dept's. that took lots of photos for advertising purposes, so it can be assumed that the Pennsy, NYC, and B&O also had and did the same. Judging from multiple images shot of the dining and lounge car interiors one notices very quickly that these are staged with rearranged grouping of individuals.
Most likely paid models and/or employees drafted from management and such. Striking a pose in photographs back then was also a thing, but you're welcome to put any slant on the activities as you wish.


Chris
in New Zealand