For full scale, the Mid-Continent Railroad Museum is about an hour away in North Freedom, WI.
https://www.midcontinent.org/
Just a bit further north, there's the Riverside and Great Northern Railway, running 15" gauge live steam. It's at the site where many live steamers were once built. Still in operation, but I don't know if there is any opportunity to tour the build shop.
https://www.trains.com/trn/new...ilwaukee-county-zoo/
https://www.dellstrain.com/
There is also Hiawatha Hobbies in Waukesha, again about an hour and a half. Good web site to see if there is anything of interest in stock.