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Section 4; pages:
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Section 4: Subsidiary Signals
(Page 4 of 4)
The sub-committee of the Railway Clearing House recommended in 1929 that colour light aspects should no longer be used for subsidiary signals, and that 'optical projector' or banner signals be used in colour light areas. This was agreed by the Ministry of Transport on 26 September 1929, as was the use of the white subsidiary semaphore arm (see [4.41 - 4.47]).
The arms of the banner subsidiary signals were horizontally striped (similar to the semaphore type) and had a letter "C", "S" or "W" as appropriate printed in red on the face of the signal [4.69 - 4.74].
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[4.69] Banner Type Calling-on Signal ('on').
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[4.70] Banner Type Calling-on Signal ('off').
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[4.71] Banner Type Shunt-ahead Signal ('on').
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[4.72] Banner Type Shunt-ahead Signal ('off').
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[4.73] Banner Type Warning Signal ('on').
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[4.74] Banner Type Warning Signal ('off').
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On the LMS schemes where colour light signals were provided with marker lights (see [2.105]), a calling-on indication was given by the red marker light being extinguished and replaced by a small yellow light [4.75].
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[4.75] Calling-on Indication (LMS).
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In the Great Western Railway's early colour light signalling schemes (e.g. Cardiff, 1933), subsidiary signals took the form of an 'opal plate', normally extinguished. When illuminated, the indicator displayed an image of a semaphore arm in the 'off' position, along with a letter "C", "S" or "W" as appropriate [4.76 - 4.78].
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[4.76] Calling-on Signal ('off') (GWR).
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[4.77] Shunt-ahead Signal ('off') (GWR).
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[4.78] Warning Signal ('off') (GWR).
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The RCH sub-committee recommended in June 1934 that for the sake of uniformity, subsidiary signals in colour light areas should be of the same form as the shunting signals (see Section 3) at the same location.
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When the Cheshire Lines Committee's Manchester Central terminus was resignalled with colour light signals in 1935, the calling-on signals took the form of a small yellow aspect, with letter "C" below [4.79]. No indication was given when the calling-on signal was 'on'.
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[4.79] Calling-on Signal ('off') (CLC).
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In 1936, the MoT agreed that subsidiary signals should be the same type as ground shunting signals. Thus, the striped banner signals (see [4.69 - 4.74]) would be discontinued, and in future a disc, with plain red arm, would be used. If the signal controlled entry into the block section, a distinguishing letter "C" or "S" would be required [4.80 - 4.83]. These signals were illuminated at night.
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[4.80] Disc Type Calling-on Signal ('on').
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[4.81] Disc Type Calling-on Signal ('off').
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[4.82] Disc Type Shunt-ahead Signal ('on').
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[4.83] Disc Type Shunt-ahead Signal ('off').
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In areas where position light shunting signals were used, subsidiary signals were of the normally-out position light type. When the subsidiary signal was cleared, the two white lights would be accompanied by a distinguishing letter "C", "S" or "W" [4.84 - 4.86].
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[4.84] Position Light Calling-on Signal ('off').
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[4.85] Position Light Shunt-ahead Signal ('off').
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[4.86] Position Light Warning Signal ('off').
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In 1934, the sub-committee proposed that for colour light signals, warning acceptance should be given not by a subsidiary signal, but by the main aspect, possibly to be accompanied by a letter "W". The proposal was accepted by the MoT on 11 March 1936.
The 'draw-ahead' signal was first mentioned in a 1937 supplement to the Rule Book. Like a shunting signal (see Section 3), a draw-ahead signal authorises the driver to proceed towards the next stop signal but not to pass any shunting signal which may be at 'danger'. A draw-ahead signal would never be provided at a signal that controlled the entrance to the section ahead. A draw-ahead signal in semaphore form will be cleared to the 'off' position without any distinguishing letter being displayed [4.87 & 4.88].
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[4.87] Lower Quadrant Draw-ahead Signal ('off').
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[4.88] Upper Quadrant Draw-ahead Signal ('off').
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By 1969, it had ceased to be a requirement for the distinguishing letter "C" to be displayed by a position light type calling-on subsidiary signal (see [4.84]). From 1983, the distinguishing letters "C", "S" or "W" were removed from position light type subsidiary signals (see [4.84 - 4.86]).
