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Section 14: Temporary Speed Restriction Signs

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On 6 June 1975, a high-speed derailment occurred at Nuneaton as a result of the lights in a gas-lit TSR warning board being extinguished. This accident prompted the British Railways Board to experiment with various improved designs of warning boards and other TSR signage in the years that followed.


From c.1975, a type of floodlit warning board was in use that was rectangular in shape but had black markings at either end to form the yellow arrow [14.22].

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

From 1976, experimental electric internally illuminated TSR boards (warning boards, speed indicators and termination indicators) went on trial at various sites on the Southern Region.

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

Experimental electrically lit warning boards and TSR indicators went on trial at various sites in 1979. The new warning board was rectangular in shape, coloured yellow all over, and displayed two flashing white lights [14.23]. While the speed indication exhibited at the warning board had white figures on a blue background, the colours were transposed on the speed indicator positioned in advance [14.24]. The termination indicator had a white "T" on a blue background [14.25].

[14.23] Electrically Lit Warning Board. Click Here for Photo
Area: All Areas   Usage: High   Status: Historical
[14.24] Speed Indicator.
Area: Various   Usage: Medium   Status: Historical
[14.25] Termination Indicator.
Area: All Areas   Usage: High   Status: Historical

A similar set of signs went on trial between Nuneaton and Brinklow (London Midland Region) from December 1979. As this trial progress into the second half of 1980, the flashing white lights in the warning board (see [14.23]) were, on some occasions, experimentally replaced with steady white lights [14.26], and later, steady yellow lights [14.27].

Further trials of the new signs began on the London Midland Region in 1980 between London St. Pancras and Bedford. For these trials, the colours of the speed indicators were reversed such that they had white figures on a blue background [14.28], thus matching the speed indication displayed at the warning board (see [14.23]). This colouring was subsequently selected as standard.

[14.26] Experimental Electrically Lit Warning Board.
Area: Nuneaton - Brinklow   Usage: Low   Status: Historical
[14.27] Experimental Electrically Lit Warning Board.
Area: Nuneaton - Brinklow   Usage: Low   Status: Historical
[14.28] Speed Indicator.
Area: All Areas   Usage: High   Status: Historical

When a TSR had been advised in the notices but was not imposed or was withdrawn earlier than published, it had been the practice since 1977 to erect or retain the TSR boards at the lineside and replace the TSR speed exhibited in both the speed indicator and the warning board with the normal line speed. As an alternative arrangement, it was proposed that the speed indications should 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 [14.29 & 14.30], was on trial from 1980 and was fully introduced in 1983.

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

When electrically lit TSR signs were adopted for general use in 1981, speed indicators with a blue background (see [14.28]) became the standard form, including those that displayed differential speeds [14.31]. A warning board that referred to a differential speed restriction exhibited both speeds above the yellow plate and flashing lights [14.32]. An electrically lit warning board could display a spate indication in the usual manner [14.33].

[14.31] Differential Speed Indicators.
Area: All Areas   Usage: High   Status: Historical
[14.32] Electrically Lit Warning Board for a Differential TSR.
Area: All Areas   Usage: High   Status: Historical
[14.33] Electrically Lit Warning Board with Spate Indication.
Area: All Areas   Usage: High   Status: Historical

The directional indication was on trial from 1982 and introduced as a standard feature in 1986. This comprised an illuminated arrow indicator [14.34] fitted to a warning board to indicate that the related TSR speed indicator is situated on a left-hand or right-hand divergence ahead.

[14.34] Warning Board with Directional Indication (e.g. applicable to TSR on right-hand divergence).
Area: All Areas   Usage: High   Status: Historical

In 1982, trials commenced which entailed a black and white striped board with a central flashing white light [14.35] being positioned on the approach to various TSR warning boards (between the warning board and its associated AWS magnet). The purpose of the trials was to assess the board's effectiveness in connection with emergency speed restrictions. An emergency speed restriction is one that has not been advised in the notices, is a lower speed or applies at a time not shown. The new board was intended to provide drivers with additional warning of an emergency speed restriction ahead, replacing the former practice of stationing handsignalmen at warning boards associated with such speed restrictions. The handsignalman would place two detonators on the rail and exhibit a yellow handsignal waved slowly from side to side for each approaching train. As well as being costly to implement, the noise from the exploding detonators was often a source of public complaints.

[14.35] Experimental Emergency Indicator.
Area: Various   Usage: Low   Status: Historical

From 1986, yellow versions of the illuminated TSR signs were on trial [14.36 - 14.43], and gradually they superseded the blue signs formerly used.

[14.36] Warning Board.
Area: All Areas   Usage: High   Status: Historical
[14.37] Warning Board for a Differential TSR.
Area: All Areas   Usage: High   Status: Historical
[14.38] Warning Board with Directional Indication (e.g. applicable to TSR on left-hand divergence).
Area: All Areas   Usage: High   Status: Historical
[14.39] Speed Indicator. Click Here for Photo
Area: All Areas   Usage: High   Status: Current
[14.40] Differential Speed Indicators.
Area: All Areas   Usage: High   Status: Current
[14.41] Termination Indicator. Click Here for Photo
Area: All Areas   Usage: High   Status: Current
[14.42] Warning Board with Spate Indication.
Area: All Areas   Usage: High   Status: Historical
[14.43] Spate Indication in lieu of speed indicator.
Area: All Areas   Usage: High   Status: Current

Following the initial trials in 1982 of an indicator for use with emergency speed restrictions (see [14.35]), further trials took place in 1986 on each of the five BR regions. The indicator involved in these trials was positioned adjacent to the AWS equipment in rear of a TSR warning board, and it comprised a trapezium-shaped board with black and white diagonal stripes and two high-powered flashing white lights [14.44]. Although these trials were successful, a revised style of indicator that went on trial in 1987 was coloured with yellow and black chevrons [14.45], and this was introduced as standard the following year. Additional AWS equipment is installed in rear of each emergency indicator. A miniature version of the indicator was also introduced, on which the lower black shape is omitted [14.46]. An emergency indicator may be colloquially referred to as a 'Dalek', 'disco board' or 'Metal Mickey'.

[14.44] Experimental Emergency Indicator.
Area: Various   Usage: Low   Status: Historical
[14.45] Emergency Indicator. Click Here for Photo
Area: All Areas   Usage: High   Status: Current
[14.46] Emergency Indicator for use in areas of limited clearance. Click Here for Photo
Area: All Areas   Usage: High   Status: Current