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Section 13: Permanent Speed Restriction Signs

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At Welsh's Bridge Junction in Inverness, there are examples of a non-standard form of speed signage that has two speeds displayed on the same board in the manner of a standard differential speed restriction (see [13.59]), with a directional arrow below [13.84]. In this case, however, only the lower speed applies to the diverging line and the upper figure is a reminder of the permissible speed on the straight route.

[13.84] Permanent Speed Restriction Sign with Directional Arrow (e.g. applicable to right-hand divergence).
Area: Inverness   Usage: Low   Status: Uncertain

In 1996, special speed restriction signs applying only to "Merry-Go-Round" (MGR) coal trains consisting of HAA type coal hoppers (loaded or empty) were erected at two locations on the London North Eastern Zone. One was across Yarm Viaduct (20 m.p.h. restriction) and the other between Ferrybridge and Milford Junction, over the curve in the vicinity of the former Burton Salmon Junction (30 m.p.h. restriction). The commencement of each special speed restriction is marked by a sign showing the speed figure below a silhouette of a hopper wagon [13.85]. The termination of the special restriction is denoted by a sign that is similar but additionally has a black cross superimposed [13.86].

[13.85] MGR Permanent Speed Restriction Commencement Sign.
Area: LNE Zone   Usage: Low   Status: Uncertain
[13.86] MGR Permanent Speed Restriction Termination Sign.
Area: LNE Zone   Usage: Low   Status: Uncertain

An advantage of the old 'cut-out' speed restriction signs (see [13.17]) over modern reflectorised types was their continued readability even when covered with graffiti or brake dust. An experimental speed restriction sign, for use in places where brake dust or graffiti problems were known to exist, was provided at Herne Hill (Southern Zone) in 1999. It was similar in appearance to a standard reflectorised speed restriction sign (see [13.43]) but with the numerals cut out.

In 1999, combined signs were installed on the approaches to Buriton Tunnel (Southern Zone), indicating a permanent speed restriction of 40 m.p.h. that applies only to Class 442 'Wessex Electric' units and HSTs [13.87]. Combined warning indicators were also provided [13.88]. These signs replaced separate signs with "HST" and "WES" speeds previously installed at the same location.

[13.87] Non-standard Differential Permanent Speed Restriction Sign (combined).
Area: Buriton Tunnel   Usage: Low   Status: Historical
[13.88] Warning Indicator applicable to a non-standard differential permanent speed restriction (combined).
Area: Buriton Tunnel   Usage: Low   Status: Historical

In 2000, non-standard differential speed restriction signs were installed on the line between Whitlingham Junction and Sheringham (East Anglia Zone), with higher speeds applicable to Class 150 - 170 trains. These signs are unusual in that the letters "SP" are below the relevant speed value [13.89]. Where warning indicators are provided, however, the lower indicators have the letters "SP" above the speed value in the normal fashion (see [13.54]).

[13.89] Non-standard Differential Permanent Speed Restriction Sign.
Area: Whitlingham Junction - Sheringham   Usage: Medium   Status: Uncertain

A non-standard differential speed restriction sign with the code letters indicating the type of train placed below the relevant speed value also exists with both speeds combined on a single sign [13.90].

[13.90] Non-standard Differential Permanent Speed Restriction Sign (combined).
Area: Various   Usage: Low   Status: Uncertain

The introduction of Class 221 and 390 tilting trains to the West Coast Main Line brought significant changes to speed signage. Tilting trains can negotiate curved track at a higher speed than non-tilting trains without unduly affecting passenger comfort. The higher speed, applicable to tilting trains provided that their tilting mechanism is in working order, is shown on an "Enhanced Permissible Speed" (EPS) sign. If the tilt mechanism has failed, the train must not exceed the lower permissible speed. Tilting trains have an "EPS authorised" indication in the cab, which must be illuminated while running in accordance with the speeds exhibited on the EPS signs.

Experimental EPS signage was put on trial at two sites on the West Coast Main Line in February 2001. The trial sites were at Linslade Tunnel and Norton Bridge. Two types of EPS signs were trialled [13.91 & 13.92], along with an experimental EPS warning indicator [13.93]. These experimental signs all showed random letters in place of a speed figure.

[13.91] Experimental EPS Sign.
Area: Linslade Tunnel / Norton Bridge   Usage: Low   Status: Historical
[13.92] Experimental EPS Sign.
Area: Linslade Tunnel / Norton Bridge   Usage: Low   Status: Historical
[13.93] Experimental EPS Warning Indicator.
Area: Linslade Tunnel / Norton Bridge   Usage: Low   Status: Historical

Further trials of experimental EPS signage took place at Linslade Tunnel and Norton Bridge in April 2001. Three different styles of EPS signs were trialled [13.94 - 13.96], along with a range of experimental EPS warning indicators [13.97 - 13.99].

[13.94] Experimental EPS Sign.
Area: Linslade Tunnel / Norton Bridge   Usage: Low   Status: Historical
[13.95] Experimental EPS Sign (subsequently adopted as standard). Click Here for Photo
Area: Linslade Tunnel / Norton Bridge (subsequently All Areas)   Usage: High   Status: Current
[13.96] Experimental EPS Sign.
Area: Linslade Tunnel / Norton Bridge   Usage: Low   Status: Historical
[13.97] Experimental EPS Warning Indicator.
Area: Linslade Tunnel / Norton Bridge   Usage: Low   Status: Historical
[13.98] Experimental EPS Warning Indicator.
Area: Linslade Tunnel / Norton Bridge   Usage: Low   Status: Historical
[13.99] Experimental EPS Warning Indicator (subsequently adopted as standard).
Area: Linslade Tunnel / Norton Bridge (subsequently All Areas)   Usage: Low   Status: Obsolescent

Where an EPS sign is provided, it is always installed underneath a standard permissible speed sign, never in isolation. Similarly, an EPS warning indicator is always installed below a standard warning indicator. Following the trials with the experimental signs, the forms of EPS sign and warning indicator chosen to become standard were, in both cases, those bearing the letters "EPS" on a yellow background (see [13.95 & 13.99]). The first stretch of line to be fitted with the new standard EPS signs was between Carnforth and Upperby Junction (Carlisle) in December 2001, for test purposes only. Those signs were removed in 2003 but EPS signs have since been progressively installed along the West Coast Main Line.

The Tyne & Wear Metro extension to South Hylton opened in 2002. To gain access to the new branch line, the light rail Metro units share tracks with heavy rail trains between Pelaw and Sunderland. As previously noted, the standard form of permissible speed sign on Railtrack infrastructure (see [13.43]) was identical in appearance to the speed signs on the Tyne & Wear Metro system but in the latter case the speed referred to is in kilometres per hour, not miles per hour. To remove the potential for confusion, a new design of speed sign, indicating "kmh" was introduced for Metro units. The new "kmh" signs are hexagonal in shape and on the joint running sections of line are mounted below the normal permissible speed signs [13.100]. Similarly, an additional "kmh" board with a yellow border is mounted below a normal warning indicator [13.101]. Most of the "kmh" speed signs do not show a direct conversion of the speed in miles per hour exhibited above. The new hexagonal speed signs were progressively installed throughout the Tyne & Wear Metro system, replacing the original circular signs.

[13.100] Permanent Speed Restriction Sign with metric sign applicable to Metro units.
Area: Pelaw - Sunderland   Usage: Medium   Status: Current
[13.101] Warning Indicator with metric sign applicable to Metro units.
Area: Pelaw - Sunderland   Usage: Low   Status: Current