I have seen similar, of fans on the Moffat Sub, and in the Price River Canyon, practically standing on top of each other. Crazy how some will drive like maniacs to get in front of the train again. I always kind of enjoyed it but some guys I work with are bewildered. If we had an extra "wheeler" it might get tossed out a window, rubber banded. I hope those folks enjoyed it.
You found a photo of the one on reddit. There was only a single prototype car built, which makes the UP sighting so rare. The Budd Lo-Pac design quickly ended up at Thrall. This version of the car is the classic A-Line/Intermountain model: https://www.intermountain-railway.com/ho/html/47301.htm I've never seen a model of the original Budd car, but it would have very limited appeal; I don't think it lasted very long. Wil's photo here, as well as these two on rrpicturearchives were both taken in 1981: http://www.rrpicturearchives.net/rspicture.aspx?id=781001 The Reddit photo also lists early 1980's, but I have never seen any other photos of this car, so maybe it was scrapped early. I don't think there were any orders of the Budd car directly, but CN was the most interested. They did end up having a derivative design built after Thrall got the car from Budd. As far as I can tell, these are those cars, built by NSC: http://tracksidetreasure.blogspot.com/2019/09/cn-lasers-five-paks-and-double-stacks.html
It likely was a case of being at the right place at the right time. The photos were taken during a convention or a club outing of some kind. No further photos were shot of that particular consist, so that is the best it is going to get.
Safety, who needs it. Wyoming, Autumn 1981 (Beyer Patton) Hustling along, Wyoming, Autumn 1981 (Beyer Patton)
When I retired, I told my fellows I was going to manufacture plexiglass windows for the lower abdomen so some folks could see where they were going.
That's an RCU SD45 in the "Safety First" pic... They were put in storage right around this time, and never used again.
UP CA-9 Caboose 25653, Wyoming, Autumn 1981 (Beyer Patton) A SD45 trio near Cheyenne, Autumn 1981 (Beyer Patton)
D&RGW Coach 1120 "Silver Aspen", Denver, CO, Spring 1974 (Beyer Patton) D&RGW Dome Buffet-Lounge-Dorm 1140 "Silver Shop", Winter Park, CO, Spring 1974 (Beyer Patton)
D&RGW Dome Coach 1107 "Silver Mustang", Winter Park, CO, Spring 1974 (Beyer Patton) Waiting at Winter Park, Spring 1974 (Beyer Patton)
These pictures show one thing missing from Amtrak. (Aside from real style.) The car naming. That was a neat promotional idea.
That's the way to go! There's something wrong with that kid... he's completely oblivious to the train with 3 engines sitting there. That just ain't natural!
A CP cylindrical hopper, Vancouver Island, BC, October 1970 (Beyer Patton) CP Road Car 403175, Victoria, BC, October 1970 (Beyer Patton)
A bit of switching at Victoria, BC, October 1970 (Beyer Patton) CP RDC-2 9199, Nanaimo, BC, October 1970 (Beyer Patton)
With an S3, no less! The guy on top seems quite nonchalant about his situation... hands in his pockets and all...