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Section 3: Shunting Signals

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On the Cheshire Lines Committee, any miniature colour light shunting signal that was associated with a main colour light signal did not display a 'stop' aspect, the red aspect in the main signal providing the 'danger' indication. When the shunting signal was cleared, an illuminated letter "S" was displayed in conjunction with the green light [3.76].

[3.76] Miniature Colour Light Shunting Signal, associated with a main signal ('off').
Area: CLC   Usage: Medium   Status: Historical

In 1935, the Southern Railway began providing floodlighted shunting signals [3.77 - 3.80] in colour light signalled areas, which satisfied the recommendation of the Railway Clearing House sub-committee from the previous year. Floodlighted signals present the same appearance to drivers during darkness as they do in daylight.

[3.77] Floodlighted Disc Shunting Signal ('on'). Click Here for Photo
Area: Predominantly Southern Railway   Usage: High   Status: Obsolescent
[3.78] Floodlighted Disc Shunting Signal ('off').
Area: Predominantly Southern Railway   Usage: High   Status: Obsolescent
[3.79] Floodlighted Yellow Miniature Semaphore Shunting Signal ('on').
Area: Southern Railway   Usage: Medium   Status: Historical
[3.80] Floodlighted Yellow Miniature Semaphore Shunting Signal ('off').
Area: Southern Railway   Usage: Medium   Status: Historical

Around this time, some areas of the LNER were providing illuminated banner shunting signals (see [3.36 & 3.37] and [3.58 & 3.59]) in their power signalling schemes (e.g. Edinburgh Waverley West, October 1936).


From around the same time, where a miniature semaphore signal controlled movements from a siding onto a running line in a colour light signalled area on the Southern Railway, it showed a yellow light when cleared [3.81], instead of showing the usual green light. This helped to maintain the principle that a green light should not lead directly to a red signal in a colour light area.

[3.81] Siding Signal with Yellow Light ('off').
Area: Southern Railway   Usage: Medium   Status: Historical

As part of the resignalling between London Waterloo and Hampton Court in May 1936, the Southern Railway installed 'auxiliary running signals' at certain main signals. These were always associated with a main colour light signal and offset to the left or right of it. The positioning of the auxiliary running signal relative to the main signal indicated to which side of the main line the applicable destination lay. Normally a small red light was displayed in the auxiliary running signal [3.82]. When cleared, this was replaced by a small yellow light [3.83], authorising the main signal to be passed for a movement into a goods loop or refuge siding, etc. Where necessary, a signal could be provided with two auxiliary running signals, one to the left and one to the right of the main signal.

[3.82] Auxiliary Running Signal ('on').
Area: Southern Railway   Usage: Medium   Status: Historical
[3.83] Auxiliary Running Signal ('off') / Miniature Yellow Aspect ('off') (e.g. reads to a line diverging to the left of the main line). Click Here for Photo
Area: Southern Railway (subsequently All Areas)   Usage: High   Status: Obsolescent

Within a matter of weeks, the Southern Railway decided to dispense with the red lights in auxiliary running signals, and thereafter they were normally unlit but still capable of displaying a yellow light when cleared. In a few later installations, an auxiliary running signal was placed below a main colour light signal rather than being offset to one side.

Position light shunting signals were installed under a resignalling scheme at Brunswick (Cheshire Lines Committee) in February 1937. Unlike those signals already in use on the North Eastern Area of the LNER in which the 'stop' aspect was two white lights (see [3.71]), the equivalent aspect shown by the CLC's signals was reinforced by the provision of a red lens in the left-hand light [3.84]. The LNER's North Eastern Area did provide a red light in some position light shunting signals when Leeds New station was resignalled in April 1937, but only at those signals that protected facing trap points or a derailer, where better stopping power was desired. This resulted in an apparent throwback to earlier practice, which saw a mix of shunting signals with either red or white lights within the same layout, as encouraged by the BoT in 1914. In any case, the North Eastern Area of the LNER reverted to providing position light signals with all white lights in subsequent resignalling schemes.

The LMS made extensive use of position light shunting signals in its resignalling at Crewe in 1940, and each signal had one coloured lens. Where appropriate, the red lens in the 'on' aspect was replaced by a yellow lens [3.85] to denote that the signal may be passed without being cleared, for a movement in a direction for which the signal when cleared did not apply. Around 1950, British Railways settled on the provision of one coloured lens in the 'on' aspect of all position light shunting signals as standard, and this form of shunting signal was adopted by every region, albeit not by the Southern Region until the early 1960s. The signals with a red lens did have to be operated to display a 'proceed' aspect when facing in the route ahead of a main signal, to prevent drivers from having to pass a red light.

[3.84] Position Light Shunting Signal with one Red Light ('on').
Area: All Areas   Usage: High   Status: Obsolescent
[3.85] Position Light Shunting Signal with one Yellow Light ('on').
Area: All Areas   Usage: High   Status: Obsolescent

On the LMS, the miniature green signal [3.86] was introduced by 1940 as an equivalent to the 'auxiliary running signals' on the Southern Railway (see [3.83]), and these showed a green light when cleared, instead of yellow.

[3.86] Miniature Green Signal ('off') (e.g. reads to a line diverging to the right of the main line).
Area: LMS   Usage: Medium   Status: Historical

Following nationalisation of the railways in 1948, the Southern Railway's 'auxiliary running signals' (see [3.83]) became a standard feature across all the British Railways regions, but were referred to as 'miniature yellow' (or 'small yellow') aspects.

Outside the Southern Region, a yellow-banded variety of floodlighted disc signal [3.87 & 3.88] was being used in some colour light signalled areas to indicate that the signal could be passed without being cleared, for a movement in a direction for which the signal when cleared did not apply.

[3.87] Floodlighted Yellow Disc Shunting Signal ('on').
Area: Various   Usage: Medium   Status: Historical
[3.88] Floodlighted Yellow Disc Shunting Signal ('off').
Area: Various   Usage: Medium   Status: Historical

In practice, it was found that floodlighting tended to cause a yellow band on a disc signal to merge with the white background (see [3.87 & 3.88]) during darkness, making it difficult to discern. The yellow-banded disc signals introduced by the Southern Region in the early 1960s avoided this problem by having a black background [3.89 & 3.90].

[3.89] Floodlighted Yellow Disc Shunting Signal with Black Background ('on').
Area: Predominantly Southern Region   Usage: High   Status: Obsolescent
[3.90] Floodlighted Yellow Disc Shunting Signal with Black Background ('off').
Area: Predominantly Southern Region   Usage: High   Status: Obsolescent

In November 1961, the S&T Committee agreed to adopt the black background as standard for all yellow disc signals, including those that were not floodlighted and retained the coloured light indications for use during darkness [3.91 & 3.92].

[3.91] Yellow Disc Shunting Signal with Black Background ('on'). Click Here for Photo
Area: All Areas   Usage: High   Status: Obsolescent
[3.92] Yellow Disc Shunting Signal with Black Background ('off').
Area: All Areas   Usage: High   Status: Obsolescent

From 1962, the miniature yellow aspect (see [3.83]) was no longer to be used on new schemes, and a position light signal was to be provided instead. Since the practice of co-locating more than one position light signal had ceased around the same time, greater reliance was placed on the use of alphanumeric route indicators (see Section 6) to distinguish between different shunting routes from the same signal.

In March 1987, a position light shunting signal at Gresty Lane, Crewe, (London Midland Region) was replaced on a trial basis by an experimental fibre-optic type of shunting signal. The 'on' aspect was a red horizontal bar [3.93], and the 'off' aspect comprised two short white bars inclined at an angle of 45° [3.94]. The experimental signal was replaced by an ordinary position light signal in March 1989.

[3.93] Experimental Fibre-Optic Shunting Signal ('on').
Area: Gresty Lane, Crewe   Usage: Low   Status: Historical
[3.94] Experimental Fibre-Optic Shunting Signal ('off').
Area: Gresty Lane, Crewe   Usage: Low   Status: Historical

The position light shunting signals that displayed one coloured light and one white light for the 'on' aspect (see [3.84 & 3.85]) had one weakness. This type of signal had often been inadvertently passed at 'danger' on occasions when failure of the coloured light had caused a single white light to be displayed alone. To overcome this, a new design of position light signal was introduced from 1996. Whilst the 'off' aspect remained unchanged, consisting of two white lights as before (see [3.72]), the new 'on' aspect comprised a pair of coloured lights, both lights being either red [3.95] or yellow [3.96] as appropriate. Note that the 'stop' indication in the signal with two red lights is identical to the standard form of 'limit of shunt' indicator previously introduced in 1985 (see [5.7]).

[3.95] Position Light Shunting Signal ('on'). Click Here for Photo
Area: All Areas   Usage: High   Status: Current
[3.96] Yellow Position Light Shunting Signal ('on'). Click Here for Photo
Area: All Areas   Usage: Medium   Status: Obsolescent

Further installations of yellow shunting signals were forbidden from 2002; however, it remains permissible to renew the older style of position light signal (see [3.85]) with one of the new design (see [3.96]), as was done at Littlehampton in March 2003. In addition, a position light signal with two yellow lights has been installed as a replacement for a mechanical yellow shunting signal.