Yes - the Midcontinent Museum is a nice outfit. The trackage is rather short at 4 miles or so but it's a pretty ride in the summer and fall. The narrow gauge boxcar you refer to is one of the C&NW 3 footers.
Here's their link. [
www.midcontinent.org]
My father was a music professor at the University of Wisconsin-Madison and put together a folk music show regarding trains in US history and he got a grant to have it filmed. The Museum agreed to let it be filmed there. This was back in 1971 or 72. I was a kid of 11 at the time and my father pulled me from school to be there for the filming. The engineer let me ride all day in the cab of D&R #9. Best day of my life. (at that time!) At that point I was a big time HO modeler of diseisels. After that day no more!
I haven't been there since the late 80's so it was nice to see pictures of there again. Thanx!
Dan