Well, there was an outfit in the post-war era called Kasiner Hobbies that made streamline cars out of extruded aluminum. I hit the book and saw a photo taken in 1952 at the NYSME layout showing those cars, although not in any great detail. At any rate they're running on the O scale layout. Whether they made them in S gauge is anyone's guess.
I wish someone would do a definative history of model railroading. The late Hal Carstens came close with his "150 Years Of Train Models," I've got a copy, but the book's a bit of a disappointment. Instead of telling the story in a linear flow it's kind of a rambling, shambling narrative, more like a "remember when" bull session of veteran modelers than a serious study. All the big names are there, and there were a lot more manufacturers of model railroad kits than you'd imagine, but they're all over the place, and no index. You really have to wade through the book to find what you're looking for. A bit frustrating, to say the least.
Like I said, that film raises more questions than it answers.
But oh wow, isn't that "Royal Blue" engine gorgeous?