Numerous closely-spaced signal boxes and associated semaphore signals once controlled every aspect of train movement in the country. Using David Hucknell all offers a pictorial history of signal boxes. This is a collection with accompanying text which covers a broad range of signal-boxes, from those built in the 1880s to examples from the 1930s, 40s and 50s. It shows the buildings and interior views of lever frames, block instruments and section maps.