A detailed history of the electrically powered bells which were used to warn staff and passengers of approaching trains. This book looks at the technical aspects of these bells, studying how they developed and changed, replacing a person who would ring the bell to warn of an approaching train. Looks at a large number of bell types. The bells were a German invention, but were widely used around Europe. Well illustrated with black & white photographs and diagrams. German text. Hardback. 264 pages.