Section 7: Co-acting Signals and Repeater Signals
(Page 1 of 3)
There are situations where a sufficiently early view cannot be obtained of a signal due to curvature or an intervening overbridge or station canopy, etc. One way to overcome this is to provide duplicate co-acting signals at the same position but at different heights [7.1]. In some examples, only the lower arms had lamps, and in some cases not every arm was duplicated [7.2]. Exceptionally, the duplicate signals were positioned on the opposite side of the line [7.3] or the arms may be arranged differently [7.4].
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[7.1] Co-acting Semaphore Signals. *
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[7.2] Co-acting Semaphore Signals. *
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[7.3] Co-acting Semaphore Signals. *
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[7.4] Co-acting Semaphore Signals. *
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| * Note: |
The above illustrations serve only to show the positions of the signal arms. For full details of their appearance, refer to Section 2. |
The famous 'bedstead' signal gantry erected on the London & North Western Railway at Rugby in 1895 represented the ultimate in co-acting signals, with all twenty-two arms being duplicated.
In some places where an early view could not be obtained of a signal, a separate 'repeater' signal would be provided on the approach. Originally these took the form of specially-distinguished semaphore signals that worked in conjunction with the signal ahead to which they referred [7.5 - 7.10]. A train need not be stopped at a repeater signal in the 'on' position and it may draw up to the main signal.
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[7.5] Semaphore Repeater Signal ('on').
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[7.6] Semaphore Repeater Signal ('off').
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[7.7] Semaphore Repeater Signal ('on') (LB&SCR).
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[7.8] Semaphore Repeater Signal ('off') (LB&SCR).
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[7.9] Semaphore Repeater Signal ('on') (L&SWR).
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[7.10] Semaphore Repeater Signal ('off') (L&SWR).
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Banner type repeater signals began to appear following the patenting of an improved design of banner signal by the W.R. Sykes Interlocking Signal Co. in 1909. Banner signals with red arms had already been used as main signals (see [2.68 - 2.71]) and shunting signals (see [3.29 & 3.30]), so it would be necessary to specially distinguish those used as repeaters. On the London Brighton & South Coast Railway, this was achieved by endorsing the face of the signal with a letter "R" [7.11 & 7.12]. If repeating a distant signal, a fishtail notch was cut into the left-hand end of the arm [7.13 & 7.14].
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[7.11] Banner Repeater with Red Arm ('on').
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[7.12] Banner Repeater with Red Arm ('off').
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[7.13] Fishtailed Banner Repeater with Red Arm ('on').
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[7.14] Fishtailed Banner Repeater with Red Arm ('off').
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In 1916, the London & South Western Railway installed colour light repeaters on the platform roads at Waterloo.
At a few locations, electric light fog repeaters were provided. The lights in these signals were normally extinguished, being exhibited only when fog or falling snow caused poor visibility conditions. The fog repeaters installed on the Ealing & Shepherd's Bush Railway (GWR) in 1920 displayed an orange aspect [7.15] if the signal being repeated was at 'danger', or a green aspect [7.16] if the signal was at 'caution' or 'clear'. The words "Fog Repeater" were written on the face of the repeater, as was the number of the signal to which it referred.
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[7.15] Fog Repeater ('on') (e.g. refers to signal number S81).
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[7.16] Fog Repeater ('off') (e.g. refers to signal number S81).
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By 1922, the Great Northern Railway was using semaphore repeater signals comprising a yellow 'somersault' type arm endorsed with a letter "R" [7.17 & 7.18].
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[7.17] Semaphore Repeater Signal ('on') (GNR).
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[7.18] Semaphore Repeater Signal ('off') (GNR).
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