This book describes the Diesel and Electric locomotives used on the main line and export mineral railways in Australia, and the operating preserved steam locomotives used both on preserved lines and on main lines.
The diesel locomotives are listed according to the type of Diesel engine used and are arranged to show the development of a particular type of locomotive, with the entries progressing from lower power to higher power units. This layout was selected to show the similarity of types used on different systems, particularly in the era of the State government railways. The electric locomotives are grouped by system in chronological order, since there was much less influence from the manufacturer than was the case with Diesel locomotives. Steam locomotives are organised by wheel arrangement, since this brings together similar locomotives from different systems, much as does the section on diesel locomotives
The book covers all the diesel and electric locomotives used by the Australian main line railways whether still in service or not. Relatively few diesel types have disappeared completely, many diesel locomotives now being used for secondary duties by smaller operators or leased by larger operators as required.
The illustrations have been chosen to show the distinctive features of the locomotives concerned to assist in using the book to identify locomotives in the field, and the book format is intended to allow easy portability.