Modern telecommunications systems for train control

In the field of railway engineering, telecommunications and signalling have been together since the very start of the application of these technologies to railway operations. This started as early as 1837 when a simple telegraph system was installed between Euston Station and Camden to enable railway policemen to control trains coming up and down the gradient. Within a few years the basic telegraph had expanded into the block signalling system still used today on some lines. As telephones took over from telegraph, so the benefits of person to person communication were brought to bear on railway operations. Communication enables signallers to keep in touch with each other, and with the over-seeing “control” which determines the priority of passage of trains. When there are problems, drivers need to be able to speak to the signallers to summon assistance or to get round equipment failures. The introduction of radio systems offers instant communication to the driver, enabling the driver to be warned of impending danger even before the signalling system can provide a warning. Remote control of signalling equipment needs communication channels to transfer the data. Looking to the future, this will become even more important as radio based signalling systems depend upon the communications medium to keep trains running. Signalling and telecommunications remain closely allied technologies.