Thanks, Mallory and Jim.
I hadn't realized Gunnison to Montrose was dropped more-or-less coincidentally with the Shavano introduction. So the car in Montrose in 1940 must be there for some "special" purpose (excursion train, extra train due to bridge outage, etc.).
I ran across another picture of an excursion train on Marshall Pass with Chili line cars (with the conductor's window boxes), but I think it was a bit later (1948 maybe?). Anyway, gives a bit of credence to those of us wanting to use our Blackstone cars on the Gunnison line before we get around to modelling the Shavano proper....
Cheers,
Jeff.