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Section 14: Temporary Speed Restriction Signs

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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 TSR indicators went on trial in 1979. The new warning board was rectangular in shape, coloured yellow all over, and displayed two white flashing lights [14.22]. 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 [14.23]. The termination indicator had a white "T" on a blue background [14.24].

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

When a TSR had been advised in the notices but not imposed or was withdrawn earlier than published, it had been the practice that normal line speed would be shown in both the speed indicator and the warning board, in place of the TSR 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 [14.25 & 14.26], was on trial from 1980 and fully introduced in 1983.

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

When battery-lit signs were adopted for general use at TSRs in 1981, the colours of the speed indicators were reversed such that they had white figures on a blue background [14.27 & 14.28], thus matching the speed indication displayed at the warning board (see [14.22]). In the case of a warning board referring to a differential speed restriction, both speeds were exhibited above the yellow plate and flashing lights [14.29]. A battery-lit warning board may display a spate indication in the usual manner [14.30].

[14.27] Speed Indicator.
Area: All Areas   Usage: High   Status: Historical
[14.28] Differential Speed Indicators.
Area: All Areas   Usage: High   Status: Historical
[14.29] Battery-lit Warning Board for a Differential TSR.
Area: All Areas   Usage: High   Status: Historical
[14.30] Battery-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 comprises an illuminated arrow indicator [14.31] fitted to a warning board to indicate that the related TSR speed indicator is situated on a left-hand or right-hand divergence ahead.

[14.31] 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 [14.32] 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.

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

From 1986, yellow versions of the illuminated TSR signs were on trial [14.33 - 14.40] and gradually they superseded the blue signs formerly used.

[14.33] Warning Board.
Area: All Areas   Usage: High   Status: Historical
[14.34] Warning Board for a Differential TSR.
Area: All Areas   Usage: High   Status: Historical
[14.35] Warning Board with Directional Indication (e.g. applicable to TSR on left-hand divergence).
Area: All Areas   Usage: High   Status: Historical
[14.36] Speed Indicator. Click Here for Photo
Area: All Areas   Usage: High   Status: Current
[14.37] Differential Speed Indicators.
Area: All Areas   Usage: High   Status: Current
[14.38] Termination Indicator. Click Here for Photo
Area: All Areas   Usage: High   Status: Current
[14.39] Warning Board with Spate Indication.
Area: All Areas   Usage: High   Status: Historical
[14.40] 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 [14.32]), further trials took place in 1986 on each of the five B.R. Regions. The new design of indicator, with two high-powered flashing lights [14.41], was positioned adjacent to the AWS equipment in rear of a TSR warning board. While the trials were a success, a revised version of indicator [14.42] was on trial in 1987 and 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 [14.43]. An emergency indicator may be colloquially referred to as a 'Dalek', 'disco board' or 'Metal Mickey'.

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

The 'repeating warning board' was introduced in 1992. The original form of board had a black letter "R" on a white background, above a miniature representation of a warning board [14.44]. It serves as a reminder to drivers of a TSR ahead, where a station platform intervenes between the warning board and the speed indicator. If the TSR speed indicator is less than 300 yards ahead of the platform then no repeating warning board need be provided. In 1993, use of the repeating warning board was extended to include connections from sidings that fall between the warning board and the speed indicator.

[14.44] Repeating Warning Board. Click Here for Photo
Area: All Areas   Usage: High   Status: Historical