If I understand that last link in the OP, all stops are in the "viewing only" class of stop. It also explains what "viewing only" means.
"Viewing Only – Locations where fans can safely view the Big Boy. In some cases, the Big Boy will be displayed behind a fence or other perimeter. Unlike display days, the Experience the Union Pacific Rail Car will not be available for tours and merchandise will not be sold. Unless otherwise noted on the schedule, all stops are "viewing only" locations."
I'd like to attend one of the "showings," but I'd want more access around the engine for photographs so I could photograph details of the "running gear" and other mechanical things. According to the description above, some may be a situation where one can't get close to it at all.
Monday, November 18
Kansas City, Mo.
Union Station
30 W. Pershing Rd.
ON DISPLAY: 9:00 a.m. – 3:00 p.m. CT