Basic train signalling & Virtual tour of Crewe Junction Signal Box

Ian Payne.

    Ian Payne during an earlier part of his career in the early 1990’s successfully trained and operated as a Signalman in signal boxes in and around Shrewsbury. This placed him in an ideal position to give members an in depth talk and presentation on this subject where its importance on maintaining safety on our railway network cannot be overstated.  Ian acted as Signalman as mentioned at many of the local signal boxes and was particularly associated with Crewe Junction Signal Box at the north end of Shrewsbury Station.

His presentation was in two parts; firstly, a review of the history of signalling and block systems  and secondly after a tea break, a virtual tour of Crewe Junction Signal Box and its signalling equipment , together with a look at some of the signals in use at Shrewsbury Station controlled by Crewe Junction.

    He outlined the history of signalling from its early block systems which were only controlled on a time interval basis. The inherent dangers in such a method of train control were obvious when a train might unexpectedly break down etc. This led the railway authorities being obliged to introduce the absolute block system where train movements are controlled by the interlocking of points and signals by mechanical levers and signal boxes being linked together and communicating with each other by bell codes to keep the whereabouts of train movements known at all time.

    Ian explained the various items of equipment in a signal box to help in this respect. There are upwards of 50 bell codes to readily identify the type of train and its movement. In addition each Signalman has to master the Signalmans Rule Book, a massive tome in itself  but not only that each Box has its own local instructions for the control of special train movements in its area.

    Ian produced excellent diagrams which showed how the absolute block system worked. He added a 1930’s L.M.S film extract on signalling which whilst being of its age did illustrate as well as how the system worked.

    After a break Ian gave us a virtual tour of Crewe Junction Signal Box plus a look at many of the signals around Shrewsbury, well illustrated with examples of the rolling stock in use in the 1990’s. The box was built as a joint enterprise between the G.W.R. and the L.N.W.R. in 1912. Ian’s tour took us round the many instruments in the box to help the Signalman in his duties including the block indicators and the track diagram. The box has 120 levers with 84 still in use at the time of the pictures. The complexity of the mechanical control system in the lower floors of the box was mind boggling and is a tribute to our Victorian Engineers who could produce such a system with a great deal of it still in use today.

    This was a much appreciated presentation by Ian as evidenced by the many questions from members on numerous aspects of signalling. As ever I am grateful to Sam Ryan  for the photos and for Ian’s input in this respect.

David Evans

November 2019