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Section 7: Co-acting Signals and Repeater Signals

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In May 1928, the Southern Railway installed a banner repeater signal with a black arm at Wandsworth Common [7.37 & 7.38]. It was agreed in 1929 that banner repeater signals should have black arms [7.37 - 7.40] in order to distinguish them from illuminated disc shunting signals (see Section 3).

[7.37] Banner Repeater with Black Arm ('on').	[7.38] Banner Repeater with Black Arm ('off') ( (a) - lower quadrant type; (b) - upper quadrant type ).


[7.39] Fishtailed Banner Repeater with Black Arm ('on').	[7.40] Fishtailed Banner Repeater with Black Arm ('off') ( (a) - lower quadrant type; (b) - upper quadrant type ).

If a semaphore signal has both a stop and a distant arm and a banner repeater is required, then normally both arms were repeated [7.41]. A 'splitting' banner signal [7.42] may be provided on the approach to a junction signal (semaphore or colour light).

[7.41] Combined Stop and Distant Banner Repeater (e.g. stop arm 'off', distant arm 'on').	[7.42] Splitting Banner Repeater (e.g. junction signal ahead cleared for a (lower speed) right-hand route).

A unique form of repeater signal existed at Exeter City Basin (Western Region). It repeated a semaphore signal that controlled the exit from the Basin branch and which was obscured by the curvature of the line. The arm of the repeater signal was coloured yellow with a black chevron, but was square-ended, not fishtailed [7.43 & 7.44].

[7.43] Semaphore Repeater Signal ('on') (Western Region).	[7.44] Semaphore Repeater Signal ('off') (Western Region).

In the early 1980s, a fibre-optic design of banner repeater signal was put on trial. The colours were reversed such that the 'banner' showed as an area of white light against a dark background [7.45 & 7.46]. Apparently the colours were reversed due to a perceived objection to giving an indication by the 'absence' of light, as would be the case if the 'banner' was a dark area against a light background. Later fibre-optic banner repeaters, however, gave the same indications as the traditional form (see [7.37 & 7.38]).

[7.45] Experimental Banner Repeater ('on').	[7.46] Experimental Banner Repeater ('off').

In 1992, the provision of fishtailed banner repeaters (see [7.39 & 7.40]) for distant signals was discontinued for new works.

Platform 4 at Penzance is only just long enough to accommodate a High Speed Train, and drivers of those trains had experienced difficulty in observing the platform starting signal, number PZ70. To remedy this, in 2003 a trial 'miniature close-up signal' was fitted to the existing signal [7.47]. The miniature signal was positioned below the main signal head and repeats its aspects (red, yellow or green).

[7.47] Miniature Close-Up Signal.

In July 2007, a banner repeater signal at Norton Bridge (number SC3616BR) was experimentally altered to be capable of showing three indications. The new third indication, which comprises a diagonal black bar against a green background [7.48], informs the driver that the signal ahead is displaying a green aspect (see [2.94]). This gives a driver running at maximum permissible speed the confidence to maintain full speed knowing that the signal ahead is showing green. The three-state banner repeater exhibits the usual white 'off' indication (see [7.38]) when the main signal displays any 'proceed' aspect other than green. The 'on' indication remains unchanged (see [7.37]). In November 2007, a further banner repeater, at Watford Junction (number WJ182BR), was converted to a three-state banner as part of the same trial. Even if three-state banner repeaters are adopted for permanent use, it is not intended that all existing banner repeaters will be converted to show a green indication. The green indication would only be used where it was considered beneficial.

[7.48] Three-State Banner Repeater showing 'Clear'.

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