The St. Louis Union Station model is truly amazing. In it's heyday it hosted multiple railroads including PRR, GM&O and many others. Today it is an entertainment desination and there is a large hotel under the trainshed. 20 years ago I stayed in a hotel room in the original headhouse. The front (streetside) end opposite the tower had been a hotel. Not sure if that is still operating today but the one under the trainshed is.
We were there twice this past summer to visit the acquarium under the trainshed with two different grandkids. St. Loius is only 90 minutes away and we visit often. My step-daughter and her husband had lunch today at Landry's which is in the former freighthouse at the edge of the trainshed.
I have just skimmed the video without sound so far and hope to have time to watch and listen to it all soon. I noticed that toward the end of the video they were showing the CMR Union Station building kit. I used the N scale version of that as the basis of my Art Institute of Chicago build. After buying the kit just because I liked it, I then saw the potential of using it for the Art Institute. I contacted them about purchasing several more wall sections. CMR was very helpful and in the end it was cheaper to just purchase a second kit. They cut me a break on shipping and the finished result is below.

This photo has a piece of posterboard behind the building to block out the workbench clutter but is makes it look like it has a slanted roof, which it doesn't.