The Museum of Steam Engines is an open-air railway collection on the edge of Nizhny Novgorod, focused on the locomotives and heavy machinery of the Gorky railway world. It is a straightforward display, but the size and physical presence of the engines carry the visit.
This is one for rail fans, families, and anyone interested in the industrial side of Russian cities. It sits outside the historic centre, so combine it with other outlying sights rather than trying to squeeze it between Kremlin stops.