If you love rails and train routes, make a whistle-stop tour of Narrow Gauge Rail Museum. The displays here tell the story of the role trains have played throughout history.
You'll have no end of sightseeing choices when in Nagpur. Narrow Gauge Rail Museum is a good place to start here, but there are loads of other interesting places to enjoy. Sitabuldi Fort, Gandhi Sagar Lake, and Empress Mall are not far from the rail transportation exhibition and will fill in your day nicely.