Permanent Speed Restriction Signs

The new design of reflectorised advance warning indicator introduced as standard later in 1986 was similar in shape to the trial version, but had a white background and a yellow border [13.43]. The usual shape of the sign is modified to a five-sided variant where there is limited clearance or where a wider or taller than usual board is needed to accommodate the lettering [13.44].

[13.43] Advance Warning Indicator.	[13.44] Advance Warning Indicator (alternative shape).

The Scottish Region style of reflectorised P.S.R. indicator (see [13.37]) was adopted as the standard throughout B.R. c.1987. However, in contrast to the Scottish Region practice, a directional arrow sign, where provided, would be positioned above the speed board [13.45 & 13.46]. Exceptionally, a directional arrow may point upwards [13.47], indicating that the sign applies to the straight route.

[13.45] Permanent Speed Restriction Sign with Directional Arrow (e.g. applicable to right-hand divergence).	[13.46] Permanent Speed Restriction Sign with Directional Arrows applicable to divergences in both directions.	[13.47] Permanent Speed Restriction Sign with Directional Arrows applicable to straight route as well as diverging route.

An advance warning indicator (A.W.I.) applicable to a speed restriction on a diverging route is fitted with a directional arrow pointing in the appropriate direction. The positioning of the arrow sign relative to the speed indicator followed the practice for standard circular P.S.R. signs (see [13.39] and [13.45]), i.e. the arrow was placed above [13.48], except on the Scottish Region, where it would be placed below [13.49]. Two arrows are displayed if the A.W.I. applies to restrictions of equal speed on diverging routes to the left and the right [13.50 & 13.51].

[13.48] Advance Warning Indicator with Directional Arrow (e.g. applicable to left-hand diverging route).	[13.49] Advance Warning Indicator with Directional Arrow (e.g. applicable to right-hand diverging route) (Scottish Region).


[13.50] Advance Warning Indicator with Directional Arrows applicable to diverging routes in both directions.	[13.51] Advance Warning Indicator with Directional Arrows applicable to diverging routes in both directions (Scottish Region).

A new design of standard differential speed restriction sign was introduced in which both speeds are exhibited on a single board and separated by a horizontal bar [13.52]. In areas of limited clearance, an elliptical sign is used [13.53]. A corresponding form of differential advance warning indicator, with a five-sided shape, was also introduced [13.54]. A triangular variant was used on the Western Region [13.55].

[13.52] Standard Differential Permanent Speed Restriction Sign.	[13.53] Standard Differential Permanent Speed Restriction Sign for use in areas of limited clearance.


[13.54] Advance Warning Indicator applicable to a standard differential permanent speed restriction.	[13.55] Advance Warning Indicator applicable to a standard differential permanent speed restriction (Western Region).

Permanent speed restriction signs concerning only specific types of trains were introduced throughout B.R. from c.1987. Unlike the earlier signs applicable only to HSTs (see [13.28 & 13.30]), these signs do not override any subsequent signs indicating a lower speed. There is therefore no equivalent to the termination sign (see [13.29 & 13.31]). The signs, placed at the start of each differential speed restriction, are based on the standard circular speed sign with the addition of identifying letters [13.56]. An elliptical sign is available for areas of limited clearance or for when the speed is composed of three figures, e.g. "100" [13.57].

The types of trains to which the signs may apply are identified by the codes below:

Restrictions of this type are referred to as 'non-standard differential' P.S.R.s. Generally where these signs are installed, a higher speed applies to the specified type of train indicated, except that a lower speed may apply where "LUL" or "CS" is shown [13.58]. Class 185 'Desiro' diesel multiple units, introduced in 2006, are not permitted to run at higher speeds shown on "MU" or "DMU" signs. Exceptionally, more than one code may be displayed on a sign [13.59].

[13.56] Non-standard Differential Permanent Speed Restriction Sign.	[13.57] Non-standard Differential Permanent Speed Restriction Sign.


[13.58] Non-standard Differential Permanent Speed Restriction Sign (e.g. lower speed applicable to LUL trains).	[13.59] Non-standard Differential Permanent Speed Restriction Sign.

Section 13: Permanent Speed Restriction Signs

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