If you want a more detailed guide that is more than just listings and has a lot of photos and important descriptions, this guide below has always been a favorite in my library. This is a must have for anyone who collects modern Lionel:
Though David Doyle who did the very large and very impressive guides to prewar and postwar Lionel, also did this guide of Lionel from 1900-2000.
It's not nearly as detailed in descriptions as the Kughn book nor his prewar and postwar guides, but considering how much product was made in those 30 years, it's understandable. At least this one has photos for just about everything that was made.