Standard Catalog of Lionel Trains 1900-1942 by David Doyle (2005, Paperback)

David Doyle has provided the Lionel collecting community with a superb up to date reference encompassing all pre-war gauges. It is the diversity of pre-war gauges, both in antiquity and in scope, that makes this work more of a challenge in many ways than its post-war counterpart. This guide meets the challenge with its in depth coverage of all four (2 7/8, Standard, O, and OO).
The chapter on 2 7/8 inch gauge is particularly well done and contains photographs of both original pieces and modern reproductions. The remaining chapters are organized both by gauge and type (locomotives, freight cars, passenger cars, etc and are equally descriptive. It would have been nice if this book contained a price reference by item for restorations, however the author makes a good point in his "How To Use This Standard Catalogue" section noting that "restorations vary widely.." making it difficult to assign values without examining the piece. Overall this is a very good and very current illustrated price guide.

timbuk2002