Although most signalling installed in Britain after the “Grouping” of the railway companies in 1923 conformed to the standards described in the other pages, many older signals remained in use for many years. Some of these features continued to be used in certain areas for new signals, too, so the theoretical standardisation did include regional variety. Even with the formation of the unified British Railways in 1948, individuality can still be seen today.
A few examples are illustrated here, but this page is not intended to be an exhaustive study of regional variety.
Many pre-grouping railways used rings and other shapes attached to the signal arms to identify special functions.
The example shown here is a Great Western Railway signal for outlets from sidings and goods loops to running lines.
The Great Western Railway also used a special signal for backing movements, if not catered for by shunting discs. Two holes were cut out of the signal arm to distinguish it from other signals.