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Section 14: Temporary Speed Restriction Signs

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While permanent way works are taking place or for other reasons it may be necessary to temporarily restrict the speed of trains to less than the normally permitted speed. The earliest method of advising drivers entailed positioning a handsignalman at the site of the temporary speed restriction (T.S.R.), with a further handsignalman positioned half a mile or so on the approach. The latter would place a detonator on the rail and exhibit a green handsignal waved slowly from side to side.



The Great Western Railway had introduced the warning board by 1905 [14.1]. One of these boards might be positioned on the approach to a T.S.R. if it was to continue for a long period of time. If a warning board was erected, the second handsignalman and the detonators could be dispensed with, except during fog or falling snow. The arrow shape and green colour of the warning board were clearly derived from the 'caution' indication of the GWR 'caution board' (see [1.31]). After sunset or during fog or falling snow, one green and one white lamp were displayed side by side in the warning board. Some other companies adopted the same style of warning board.

[14.1] Warning Board.
Area: Various   Usage: High   Status: Historical

If a warning board was erected, the beginning and end of the restriction might be marked by a commencement indicator and a termination indicator, respectively, instead of by handsignalman. Normal speed may be resumed as soon as the rear of the train has passed the termination indicator. On the Great Central Railway, the commencement indicator was a green oval board, which displayed two green lights side by side at night [14.2], and the termination indicator was a white diamond shaped board showing one green light at night [14.3]. The Great Eastern Railway placed a green banner and green light at the commencement of the restriction and used a termination indicator in the form of a tall white board shaped like a letter "T", showing a white light at night [14.4].

[14.2] Commencement Indicator.
Area: GCR   Usage: High   Status: Historical
[14.3] Termination Indicator.
Area: GCR   Usage: High   Status: Historical
[14.4] Termination Indicator.
Area: GER   Usage: High   Status: Historical

From 1914, the London & North Western Railway would place an indicator below the warning board, showing the speed in miles per hour that the train's speed must be reduced to [14.5]. The LNWR's commencement and termination indicators comprised white circular boards bearing the letters "C" and "T", respectively [14.6 & 14.7].

[14.5] Warning Board with Speed Indication.
Area: LNWR   Usage: High   Status: Historical
[14.6] Commencement Indicator.
Area: LNWR   Usage: High   Status: Historical
[14.7] Termination Indicator.
Area: LNWR   Usage: High   Status: Historical

From c.1916, the illuminated speed indications at LNWR warning boards were exhibited above the warning board [14.8].

[14.8] Warning Board with Speed Indication.
Area: LNWR   Usage: High   Status: Historical

Standard signage for T.S.R.s was introduced nationally in 1917. This included the existing style of warning board (see [14.1] and [14.8]) as well as new forms of commencement and termination indicators. The commencement indicator had a black letter "C" on a white background [14.9] and the termination indicator had a white "T" on a black background [14.10]. Both indicators were illuminated. For a T.S.R. located inside a long tunnel, the commencement and termination indicators could be dispensed with and audible signals given instead by means of gongs.

[14.9] Commencement Indicator.
Area: All Areas   Usage: High   Status: Historical
[14.10] Termination Indicator.
Area: All Areas   Usage: High   Status: Historical

The warning boards were altered to have white edges c.1924 [14.11 & 14.12]. The ex-LNWR practice of displaying the speed above the warning board [14.12] was subsequently followed on all LMS lines. Around 1944, the GWR and the Southern Railway adopted the same practice but the LNER did not.

[14.11] Warning Board.
Area: Various   Usage: High   Status: Historical
[14.12] Warning Board with Speed Indication.
Area: LNWR (subsequently All Areas except LNER)   Usage: High   Status: Historical

From 1938, in colour light signalling areas, the Southern Railway used electrically floodlighted warning boards, which obviated the requirement for handsignalmen to be stationed at them during fog or falling snow.

In 1949, the warning boards were repainted yellow, by then the long-accepted colour meaning 'caution'. Two lamps with yellow lenses were exhibited at night [14.13]. Gas-lit warning boards, introduced in the 1960s, exhibited two white lights instead [14.14].

[14.13] Yellow Warning Board.
Area: All Areas   Usage: High   Status: Historical
[14.14] Gas-lit Warning Board.
Area: Various   Usage: High   Status: Historical

The Operating Committee recommended in July 1965 that commencement indicators (see [14.9]) be replaced by speed indicators, which display the T.S.R. speed [14.15] in addition to the speed indication at the warning board. Speed indicators were introduced in 1968. Differential speed restrictions were introduced for T.S.R.s also in 1968. Where these are in force, the speed indicator will display two speeds, one above the other [14.16]. The warning board would also show both speeds, one above the arrow board and one below [14.17]. The speeds apply as follows:

[14.15] Speed Indicator.
Area: All Areas   Usage: High   Status: Historical
[14.16] Differential Speed Indicators.
Area: All Areas   Usage: High   Status: Historical
[14.17] Warning Board for a Differential T.S.R.
Area: All Areas   Usage: High   Status: Historical

From c.1975, a type of floodlit warning board was in use which was rectangular in shape but had black markings at either end to form the yellow arrow [14.18].

[14.18] Floodlit Warning Board.
Area: Various   Usage: High   Status: Historical

In 1978, two experimental warning boards were erected near Slough to test their effectiveness. One was equipped with white flashing lights; the other had flashing blue and white lights and blue markings.

Experimental battery-lit warning boards and T.S.R. indicators went on trial in 1979. The new warning board was rectangular in shape, coloured yellow all over, and displayed two white flashing lights [14.19]. The speed indication exhibited at the warning board had white figures on a blue background, the colours being transposed on the speed indicator positioned in advance [14.20]. The termination indicator had a white "T" on a blue background [14.21].

[14.19] Battery-lit Warning Board. Click Here for Photo
Area: All Areas   Usage: High   Status: Historical
[14.20] Speed Indicator.
Area: Various   Usage: Medium   Status: Historical
[14.21] Termination Indicator.
Area: All Areas   Usage: High   Status: Historical

When a T.S.R. had been advised in the notices but not imposed or was withdrawn earlier than published, it had been the practice that normal line speed would be shown in both the speed indicator and the warning board, in place of the T.S.R. speed. As an alternative, it was proposed that the speed indications would be replaced by a special indicator termed a 'spate' indication, 'spate' being an acronym for 'speed previously advised terminated early'. The spate indication, which comprises a diagonal stripe [14.22 & 14.23], was on trial from 1980 and fully introduced in 1983.

[14.22] Spate Indication at a Warning Board.
Area: All Areas   Usage: High   Status: Historical
[14.23] Spate Indication in lieu of a speed indicator.
Area: All Areas   Usage: High   Status: Historical