After an entertaining ten minutes or so setting up the equipment Tim gave us his talk and slide show entitled “An introduction to Signalling”.
Tim started off his working life as a signalman on the London Underground and produced a slide showing him at work in the Aldgate East signal box together with a natty tie and 1980’s haircut to prove it. Tim briefly touched on the history of signalling on the railways where the first signalmen controlled trains by means of waving a flag. Interestingly these
first signalmen were known as “Bobbies” because of their resemblance to early policemen.
Signalling developed quickly in the early days in the light of experience as a result of numerous crashes and other incidents. At first individual railway companies had their own systems and procedures but as time went on these became more and more standardised with added impetus given to this firstly by the grouping of 120 companies in 1923 and then
by nationalisation in 1948.
Tim explained the concept of block signalling and with various slides showed how this worked in practice and how signals and point work would be interlocked in order to prevent avoidable accidents. Incidentally telegraph and not telephone was the preferred means of communication between signal boxes as it was quicker and with fixed terms relating to each action or situation.
Having worked in numerous boxes on the London Underground system Tim showed us slides of many of them and explained the equipment being used in each. In many cases the equipment was a mixture of technologies some dating back to before nationalisation with more modern equipment added in from time to time up to the present day. Nowadays
with an ever increasing need to maximise capacity on the Underground network computer systems are able to control train movements to the extent that a train can safely enter a platform just as the previous train is leaving it.
After many questions of Tim on what is clearly a very large and interesting subject Tim was roundly thanked by all for his talk and we wended our way home. Chris