For anyone interested in the history of mechanical railway signalling, particularly during the development years between 1850 and 1930, this book is a must. For a reader that already has an extensive library of mechanical signalling publications, the book has to be one of the most interesting in my collection.
Although specific to the Great Northern Railway, it is full of interesting information, photographs and illustrations and is well researched. The book has been organised into relevant and logical chapters covering Organisation, Block working and Interlocking, Block instruments, Semaphores and Lamps, Signalling Contractors, Signalboxes, Single Lines, Miscellaneous Equipment and Staff. In any book on this subject there is a limit on what can be included, but the author has achieved a balanced and informative publication.
The quality of the written material, photographs and illustrations and the general layout is at the high standard one comes to expect for a book both from this author and OPC. I agree with the dust jacket comment that "... for all those who remember the sights and sounds of mechanical signalboxes, as well as those who want to know more about how railway safety was maintained before colour-lights and computers, this book should prove absorbing".