Go to Olsen’s Toy Train Parts website, which has a Library section. In that section, is a reprint of Lionel Service Manual, similar to Greenberg’s book & the Aurotech (Kline) book. It has a section on transformers, with PDF files that you can download & print. There is a wealth of info in the Library, with Post/Prewar with diagrams and part numbers. Bookmark the site for future.