UP owns and operates an elite roster of passenger equipment, reserved for special occasions and publicity events. They’re used for officer specials, steam excursions, Operation Lifesaver specials and the like. You won’t see them hauling the general public, however– that’s what Amtrak is for!
More information is available on UP’s Heritage Fleet site.
Below I am posting such shots as I have managed to take of the special cars, and will update whenever the opportunity presents. I have included hi-resolution images of both sides of the cars whenever possible.