Section 13: Permanent Speed Restriction Signs
(Page 2 of 6)
Following a derailment on the curve at Morpeth on 7 May 1969, the British Railways Board agreed to the provision of advance warning boards on the approach to certain speed restrictions. The new boards, which became known as 'Morpeth Boards', were placed at braking distance to the start of the speed restriction and in many cases were floodlit at night [13.20]. These began to appear from 1971. An advance warning board applicable to a speed restriction on a diverging route carried an additional directional arrow below [13.21].
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[13.20] Advance Warning Board.
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[13.21] Advance Warning Board with Directional Arrow (e.g. applicable to right-hand diverging route).
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The Class 253 & 254 'High Speed Trains' (or 'InterCity 125s') were introduced to British Rail in 1976. Because of their superior braking performance, they were permitted to travel over specified sections of track at a higher speed than other trains. Special signs were installed on the Eastern Region to mark the commencement and termination of the higher speed restrictions for HSTs. The commencement sign is an upward-pointing pentagon [13.22] indicating the higher speed at which HSTs may travel. Drivers of HSTs may then disregard any ordinary signs indicating a lower speed including any further signs ahead. This applies until a termination sign is reached, this being a downward-pointing pentagon [13.23] indicating the lower speed to which HSTs must revert. Ordinary speed restriction signs indicating a higher speed continue to apply.
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[13.22] Commencement Sign (Eastern Region).
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[13.23] Termination Sign (Eastern Region).
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Slightly different signs were installed on the Scottish Region from 1981. The commencement sign was square in shape [13.24], while the termination sign displayed just a letter "T" rather than the speed [13.25]. These signs may be provided in isolation or co-located with ordinary speed signs.
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[13.24] Commencement Sign (Scottish Region).
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[13.25] Termination Sign (Scottish Region).
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On the Scottish Region, higher permissible speeds applicable to Diesel Multiple Unit trains were indicated by similar signs, but with the letters "DMU" or "MU" instead of, or as well as, the letters "HST" [13.26 & 13.27]. Note that signs displaying only the letters "MU" also apply to HSTs, and vice-versa.
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[13.26] Commencement Sign (Scottish Region).
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[13.27] Termination Sign (Scottish Region).
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Differential speed restrictions had already been used for some temporary speed restrictions (see Section 14) and at certain level crossings (see Section 16). Their use was extended to apply to permanent speed restrictions, where appropriate, from 198_ [13.28]. Where an advance warning board is required, this will also show two speeds [13.29]. This form of differential speed restriction has come to be referred to as a 'standard differential' P.S.R., to distinguish them from those 'non-standard differential' P.S.R.s where the type of train is specified by letters, e.g. "HST".
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[13.28] Standard Differential Permanent Speed Restriction Sign.
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[13.29] Advance Warning Board applicable to a standard differential permanent speed restriction.
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A range of experimental reflectorised permanent speed restriction indicator signs [13.30 - 13.34] were put on trial at a site near Bishopbriggs on the Scottish Region in c.1984. One sign was simply a reflectorised version of the existing 'cut-out' design of indicator [13.30]. Another was a larger version of the standard road sign [13.33] and similar to the signs that were then in use throughout the Tyne & Wear Metro system. This one was chosen as the new standard sign for the Scottish Region in c.1985.
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[13.30] Experimental Permanent Speed Restriction Sign.
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[13.31] Experimental Permanent Speed Restriction Sign.
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[13.32] Experimental Permanent Speed Restriction Sign.
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[13.33] Experimental Permanent Speed Restriction Sign (subsequently adopted as standard).
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[13.34] Experimental Permanent Speed Restriction Sign.
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If the restriction applied to a diverging route, an arrow was placed below the speed sign [13.35 & 13.36] in a manner similar to the earlier 'cut-out' signs.
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[13.35] Permanent Speed Restriction Sign with Directional Arrow (e.g. applicable to left-hand divergence) (Scottish Region).
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[13.36] Permanent Speed Restriction Sign with Directional Arrows applicable to divergences in both directions (Scottish Region).
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In the case of a standard differential speed restriction, two signs were placed one above the other on the same post [13.37].
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[13.37] Standard Differential Permanent Speed Restriction Sign (Scottish Region).
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