Everyone has seen or even has a few “Guinness Book of World Records”. There is usually 1 or 2 pages of railroad world records. I just have to think there is a lot more world records related to railroad stuff but not sure if there is enough for a book. Maybe throw in with the book some model railroad stuff to fill a few more pages.
Largest: locomotive, freight car, passenger car, bridge, tunnel, train in weight, train in length, route round trip for a full train, passenger station.Then of course smallest or lightest etc. etc. etc. Widest gauge, narrowest gauge. I’m sure you guys/gals will think of more.