In his all-new book, Modeling the Transition Era , expert modeler Tony Koester takes an in-depth look at the time period (and most popular modeling era) when railroads were changing from steam locomotives to diesel during the 1940s and 1950s. The book includes: An overview of the era -- why diesel replaced steam. The types of railroad equipment in use. A look at typical railroad operations. The book features a mix of modeling and prototype photos to help you increase the realism and accuracy of your transition-era layout.