|
|
|
|
|
In a semaphore signalling area, lack of space could prevent a particular signal from being fitted with a semaphore arm. The arm in this instance was dispensed with, and the signal conveyed its indications by just a red or green light by day and night. The signals concerned were usually provided with intensified lighting, which produced a beam of light equivalent to a colour light signal. Although semaphore signalling practice permits a green light in one stop signal to be followed by a red light in the next, this sequence cannot normally occur in standard colour light practice. Where the LMS considered that drivers might confuse the armless signal with a normal colour light signal and wrongly take the green aspect as an indication that the next signal was also 'off', a special marker was provided. Exhibiting a black ring on a white opal background [2.125], the marker was illuminated only when the signal it was fitted to was exhibiting a green aspect and, where practicable, only if the signal ahead was at 'danger'. The lit marker advised the driver that the signal was acting like a semaphore signal, and the next signal may be at 'danger'. |
|
|
To accommodate increased wartime traffic, the GWR provided intermediate block sections through the Severn Tunnel in November 1941. The intermediate block home signal on each line took the form of a two-aspect colour light signal. As a precaution against lamp failure, the 'danger' aspect consisted of two red lights [2.126]. These signals were removed in May 1947. |
|
Two signs were installed between Wolverhampton Steel Terminal and Wednesbury Central (London Midland Region) in 1973 to act as distant marker boards for a stopping point beyond. Both signs were in the form of 'intermediate boards' (see [16.19]), which were usually intended for use on approach to a level crossing where trains are required to stop.
On 28 February 1975, an accident occurred at Moorgate on the Northern City Line, which was then part of the London Underground. A loaded passenger train ran at speed through the buffer stop and into the tunnel end wall. As a result, British Rail decided that in future all colour light signals reading into terminal platform lines would show a yellow rather than a green aspect when the line was clear to the buffer stop.
In December 1975, the yellow aspect (see [2.106]) of the single-aspect colour light distant signal on the Gravesend West branch at Fawkham Junction (Southern Region) was replaced by a yellow fluorescent disc on the existing signal post [2.127].
During bridge construction work on the Riverside branch (Newcastle) in February 1977, the site of the work was protected in each direction by a stop board reading "Stop - Await instructions" (see Section 26). An advance warning board comprising a yellow disc on a white background [2.128] was provided on the Up Branch line to act as a fixed distant signal for the stop board ahead.
 |
 |
|
[2.127] Fixed Distant Marker.
Area: Fawkham Junction Usage: Low Status: Historical |
[2.128] Advance Warning Board.
Area: Riverside branch (Newcastle) Usage: Low Status: Historical |
|---|
In May 1977, the single line through Kirkby station (London Midland Region) was divided by the installation of back-to-back buffer stops to form two terminating branch lines. A marker board was provided on the approach to each buffer stop, and although these performed the function of a fixed distant signal, they took the form of advance warning boards of the style more usually associated with level crossings (see [16.15]). A similar board was installed on the approach to the buffer stop at Blackpool South station in March 1982. All three boards were later replaced by standard reflectorised distant boards, those at Kirkby being replaced in December 1985, and the one at Blackpool South in May 1997.
Opened in May 1977, the Liverpool Loop line is an underground railway used exclusively by electric multiple units that provide an intensive passenger service. It was therefore equipped with two-aspect signalling similar to that used on most of the London Underground, which has two types of main signals, namely stop signals and repeater signals. A stop signal shows a red light for "danger - stop" or a green light for "clear - proceed". Where sighting of a stop signal is good, drivers are expected to be able to stop at a red aspect with no advance warning, but where sighting is restricted, a repeater signal is provided on approach. A repeater signal shows a yellow light for "caution - be prepared to find the next signal at danger" or a green light for "clear - proceed". A repeater signal that relates to a stop signal beyond may be co-located with the preceding stop signal. Where this occurs, the repeater signal is mounted below the stop signal, so that the 'caution' aspect comprises a green light over a yellow light [2.129], and the 'clear' aspect is green over green [2.130]. When the stop signal is displaying a red aspect, no light is shown in the repeater signal below, in contrast to the 'danger' aspect displayed by earlier combined stop and distant signals comprising separate colour light heads (see [2.109]).
 |
 |
|
[2.129] Green Aspect over Yellow Aspect.
Area: Liverpool Loop line Usage: Low Status: Current |
[2.130] Green Aspect over Green Aspect.
Area: Liverpool Loop line Usage: Low Status: Current |
|---|
|
Originally, no warning was provided to drivers on the approach to terminal stations worked by the One Train Working method (where signals were not needed), except at a few places where signs normally meant for other purposes had been misappropriated to act as marker boards (see above). In 1977, a new board was proposed for use in such situations, comprising a black diamond on a white reflectorised background [2.131]. Self-luminous 'Betalight' strips could be fitted if necessary. |
|
The introduction of the Class 253 and 254 'High Speed Trains' (or 'InterCity 125s') created the need for two additional colour light signal aspects. The new flashing aspects were designed to give drivers an advance indication that the junction signal ahead (see Section 6) is showing a 'proceed' aspect applicable to the diverging route. Where there is more than one diverging route, the flashing aspects only refer to the highest speed divergence(s). A flashing single yellow aspect [2.132] means "preliminary caution - be prepared to find the next signal displaying one yellow light, with a route indication for the highest speed diverging route". Where provided, the flashing double yellow aspect [2.133] means "proceed - next signal displaying flashing single yellow" and is an indication of a diverging route ahead of the next but one signal. The new aspects were first introduced at Didcot East Junction (Western Region) in March 1979, signals R70 and DM49 on the Down Main line being equipped to display a flashing single yellow and a flashing double yellow aspect, respectively. This installation was soon followed by others on each of the remaining regions apart from, initially, the Southern Region.
 |
 |
|
[2.132] Flashing Single Yellow Aspect.
Area: All Areas Usage: High Status: Current |
[2.133] Flashing Double Yellow Aspect.
Area: All Areas Usage: High Status: Current |
|---|
In November 1979, a marker board was erected on the approach to the buffer stop at Stourbridge Town station (London Midland Region). This followed an accident on 2 April 1977 when a train crashed through the buffer stop. Acting as a fixed distant signal, the board displayed an outline of a semaphore distant arm in the 'on' position [2.134].
Between 1980 and 1982, distant boards were being provided in place of fixed semaphore distant signals on various colliery branch lines on the Eastern Region. These comprised a square yellow board with a black chevron [2.135].
 |
|
|
[2.134] Distant Board.
Area: Stourbridge Town Usage: Low Status: Historical |
[2.135] Distant Board.
Area: Eastern Region Usage: Medium Status: Historical |
|---|
|
An experimental form of distant board appeared at Blaenau Ffestiniog (London Midland Region) c.1981, on the single line from Trawsfynydd. The board had the image of a yellow distant arm on a black background, and three self-luminous 'Betalights' were fitted across the arm to give drivers a visible indication during darkness [2.136]. Betalights had the drawbacks of being radioactive and susceptible to vandalism. |
|
In the early 1980s, a 'low cost signalling committee' was formed, tasked with developing proposals aimed at reducing the cost of signalling lightly used lines. Amongst other ideas, these included the emergence of a standard form of reflectorised distant board, following the manufacture of a number of experimental boards for evaluation purposes [2.137 - 2.140]. The style of board that was chosen to become standard [2.140] was first put into use in 1982.
 |
 |
 |
 |
|
[2.137] Experimental Reflectorised Distant Board.
Area: Unknown Usage: Nil Status: Historical |
[2.138] Experimental Reflectorised Distant Board.
Area: Unknown Usage: Nil Status: Historical |
[2.139] Experimental Reflectorised Distant Board.
Area: Various Usage: Low Status: Obsolescent |
[2.140] Experimental Reflectorised Distant Board (subsequently adopted as standard).
Area: All Areas Usage: High Status: Current |
|---|
|
A new signal aspect was introduced to facilitate special test runs of the new Class 91 electric trains on the East Coast Main Line at speeds of up to 140 mph. Most of the signals on the Fast lines between Peterborough and Stoke Tunnel were altered in May 1988 to be capable of displaying a flashing green aspect [2.141]. For the test trains, a flashing green aspect gave authority to exceed 125 mph, and a steady green aspect (see [2.107]) meant "reduce speed to 125 mph". For all other trains, a flashing green aspect has the same meaning as a steady green. |
|
In the South London area in 1992 and 1993, while resignalling work was being carried out in connection with the Channel Tunnel project, temporary block working by ticket was implemented over certain lines. The colour light signals at the exits from the affected sections were fixed at 'danger', and a handsignalman appointed at each would instruct the driver to proceed when authorised by the signalman. Because the signals in question had no lamp-proving, their 'danger' aspect comprised two red lights (see [2.126]). In the event of one light failing, the handsignalman would immediately inform the signalman.
|
|
