If the arm is raised by 45 degrees to indicate ‘PROCEED’, signal is termed ‘UPPER QUADRANT’ or, if lowered by 45 degrees to indicate ‘PROCEED’, signal is termed ‘LOWER QUADRANT’.Ĭomplementing Jan’s guide, the following illustrations from Wikipedia shows lower quadrant signal positions (shared here under CC BY-SA 3.0 license).Īn elderly Great Western signal. YELLOW: Distant caution, Green signifies Clear.īoth types of signal have two valid aspects, according to the position of the signal arm (which controls the colour of the lamp shown at night):-Īrm is horizontal (‘ON’ Aspect): ‘STOP’ (if a stop signal), ‘Proceed with Caution’ (if a distant signal).Īt night, the indications are Red light: ‘STOP'(if a stop signal), Yellow light: ‘Proceed with Caution’ (if a distant signal).Īrm is raised or lowered by 45 degrees (‘OFF’ Aspect): ‘PROCEED’.Īt night, the indications are Green light: ‘PROCEED’. Two coloured filter glasses are connected to the signal arm and move in front of the lamp according to how the signal is set. Obviously, at night train crews wouldn’t have been able to see the arms as clearly so the signals were fitted with a lamp (usually paraffin). The black and white painting of the post indicates an ‘Independent’ Distant – one not co-located with a ‘Stop’ Signal. Front of arm is RED with a WHITE vertical band near the end, rear is WHITE with a BLACK vertical band near the end.ĭarley Dale Down (fixed) Distant Signal.
#SAILOR DOING SEMAPHOR SIGNALS IMAGES DRIVER#
Signals comprise a vertical post (of wood, steel tube, steel lattice or occasionally reinforced concrete) on which is mounted one or more ‘stop’ or ‘distant’ signal arms each comprising a rectangular ‘blade’ (of wood or steel) mounted on a pivot so as to extend to the left of the signal post (viewed from an approaching train to which the signal applies) at a height to facilitate observation by the driver of an approaching train. ‘Distant’ signals – these are warning and an approaching driver may pass the signal displaying a caution or restrictive aspect but be prepared to stop at the following ‘stop’ signal.‘Stop’ signals – these are mandatory and an approaching driver must stop if the signal displays a ‘stop’ aspect.There are two principal classes of fixed signal:.
The principals of UK railway signalling are complex and rather than get it wrong, Jan Ford has kindly given permission to reproduce this guide from janfordsworld. Let’s correct that omission straight away with an introductory guide to the operation of semaphore signalling. I can’t believe I’d missed this vital aspect of railways but missed it I had. Here’s a back to basics guide on what and how semaphore signalling worked.Ī couple of readers have contacted me recently to point out that I’ve neglected to cover signalling on Model Railway Engineer. If you want your model railway to look the part, you’ll need signals and in the case of steam era railways this means semaphore signals.
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