Thanks for posting those pictures, Bruce. I had not seen them before. I have always been interested in the Chicago Railroad Fair of 1948-1949, because I lived just a few miles from the site, but was too young to attend. I wish I had been at least five years older at the time. I asked my parents if they had attended, and they had not (which is amazing to me, because it was so large an event and so close.)
I have some memorabilia from the Fair, however: a brochure, a plate, and a wooden model of the C&NW / Galena & Chicago Union "Pioneer" locomotive (which I have always assumed was from the Fair, but which also may be from the 1933 Century of Progress Exposition).