Jim Champ's grandfather was born beside the Great Western Railway in Devon and would often reminisce about watching steam locomotives before he was elected to take up a premium apprenticeship with the Metropolitan Railway in the early days of electric traction before the Great War intervened. When the author retired from a career in IT infrastructure, it seemed appropriate to reverse the process, abandon electricity and renew a teenage enthusiasm in the infrastructure of the Great Western Railway. Of the genesis of this volume, he says 'I could find no single volume giving an introduction to the Great Western Railway locomotive fleet. In my experience one of the best ways to study a technical subject is to write about it and draw it, so I did both.'