Signaling on British Railways underwent massive changes from Nationalization in 1948 to privatization in the 1990s, but throughout this period much of the network’s infrastructure dated from the era of the Big Four and the pre-Grouping companies. In this book author Robert Hendry presents a photographic portrait of the variety of traditional signaling in use in the BR era, from the pre-Grouping infrastructure and mechanical signaling up to BR-built signal boxes prior to the conversion to color-light signaling. The reader is also introduced to the principles of signaling operation.