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Section 14: Temporary Speed Restriction Signs

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Both lines across the Forth Bridge are signalled bi-directionally to allow all traffic to be worked over one line, in both directions, while the other line is out of use and under possession for engineering work. For all pre-planned work, a temporary speed restriction of 20 m.p.h. will be imposed for right-direction movements. Wrong-direction movements are subject to a 20 m.p.h. permanent speed restriction. New special arrangements for signage associated with these pre-planned temporary speed restrictions on the bridge were introduced c.1993. No warning board or AWS equipment will be provided. The speed indicator is a blue circular board [14.45], which replaces the permanent speed restriction sign that is normally exhibited on the approach to the bridge. The termination indicator has a white "T" on a blue background (see [14.24]). Drivers may accelerate as soon as the front of the train has passed the termination indicator. If the work is unplanned or the restriction is to be more severe than 20 m.p.h., standard TSR signage including warning boards and AWS will be provided.

[14.45] Speed Indicator. Click Here for Photo
Area: Forth Bridge   Usage: Low   Status: Current

In 1996, use of directional indicators, as previously used with TSR warning boards (see [14.35]), was extended for use on speed indicators [14.46] where the TSR applies through a divergence immediately ahead.

[14.46] Speed Indicator with Directional Indication (e.g. applicable to left-hand divergence).
Area: All Areas   Usage: High   Status: Current

Reflectorised boards for temporary speed restrictions were introduced from 1996, having been on trial since 1994. While this change did not alter the appearance of most of the boards, the new warning board was given two white spots [14.47 - 14.50] instead of flashing white lights. A revised design of repeating warning board, with a yellow background to the letter "R" [14.51], was introduced at the same time.

[14.47] Reflectorised Warning Board.
Area: All Areas   Usage: High   Status: Current
[14.48] Reflectorised Warning Board for a Differential TSR. Click Here for Photo
Area: All Areas   Usage: High   Status: Current
[14.49] Reflectorised Warning Board with Directional Indication (e.g. applicable to TSR on right-hand divergence).
Area: All Areas   Usage: High   Status: Current
[14.50] Reflectorised Warning Board with Spate Indication.
Area: All Areas   Usage: High   Status: Current
[14.51] Repeating Warning Board. Click Here for Photo
Area: All Areas   Usage: High   Status: Current

A track condition that presents itself as a series of regular dips in the vertical alignment is referred to as 'cyclic top'. It has the potential to cause a derailment unless a TSR is imposed. In 1998, a trial of signage indicating a cyclic top restriction [14.52] was carried out between Tonbridge and Redhill.

[14.52] Cyclic Top Restriction Sign.
Area: Tonbridge - Redhill   Usage: Unknown   Status: Historical

A reflectorised version of the emergency indicator without any lights was on trial from 1999. Following comments received from traincrews, a modified indicator was developed in 2000 incorporating two flashing white lights, as per the standard non-reflectorised design.

On 15 January 1999, a passenger train was derailed near Crosby Garrett Tunnel on the Settle & Carlisle Line and struck by a freight train heading south on the opposite line. Debris from a landslip had caused the derailment. A derailment and collision had occurred under similar circumstances on 31 January 1995 at Ais Gill on the same route, and in that incident the guard of the first train was killed by the collision.

Following an investigation into the Crosby Garrett accident, the H.S.E. issued an Improvement Notice on Railtrack requiring that it takes steps to reduce the likelihood of derailment of trains caused by landslip. The resulting arrangements put in place late in 1999 required trains to travel at a reduced speed (20 m.p.h.) during severe weather conditions at particular sites where cuttings or embankments were considered to be vulnerable to landslip. Rain gauges were installed at the sites concerned to enable a decision to be made as to whether a caution should be imposed.

Signs were permanently installed on the approach, beginning and end of each caution area, each showing "C20" on a white background surrounded by a blue border [14.53 - 14.55]. The warning board on the approach to each site additionally had two white spots on a blue background at the bottom [14.53], while the sign at the end of a caution area had a red cross superimposed [14.55]. Normally, these boards could be disregarded. On occasions when a caution was to be imposed, the driver of each train would be stopped and verbally instructed to obey the caution boards at all sites between that signal box and the next box. Additionally, the signalman would not allow another train into the affected area until the first train had passed clear.

[14.53] Caution Area Ahead Warning Board.
Area: Settle & Carlisle Line   Usage: Medium   Status: Historical
[14.54] Commencement of Caution Area Board.
Area: Settle & Carlisle Line   Usage: Medium   Status: Historical
[14.55] End of Caution Area Board.
Area: Settle & Carlisle Line   Usage: Medium   Status: Historical

During 2000, lettered boards [14.56 - 14.58] were provided on every caution board to enable each site to be individually identified. The thirteen sites were identified by the letters A to H and J to N. When a caution was to be imposed, the signalman at either Hellifield or Low House Crossing would issue the driver with a form listing at which sites the caution boards were to be obeyed.

[14.56] Caution Area Ahead Warning Board (e.g. site 'A').
Area: Settle & Carlisle Line   Usage: Medium   Status: Historical
[14.57] Commencement of Caution Area Board (e.g. site 'C').
Area: Settle & Carlisle Line   Usage: Medium   Status: Historical
[14.58] End of Caution Area Board (e.g. site 'N').
Area: Settle & Carlisle Line   Usage: Medium   Status: Historical

Following the completion of earth stabilisation works, most of the caution boards were removed in 2005.

In connection with the joint running of heavy rail trains and Tyne & Wear Metro units between Pelaw and Sunderland from 2002 (see Section 13), temporary speed restriction signs require to show speeds in kilometres per hour as well as in miles per hour. The "kmh" speed is shown on a hexagonal board below the miles per hour speed in both the warning board [14.59] and speed indicator [14.60]. Owing to the different conditions applicable only to Metro units, the "kmh" speed is not usually a direct conversion of the speed shown in miles per hour.

[14.59] Warning Board with metric sign applicable to Metro units.
Area: Pelaw - Sunderland (subsequently also Ashford International)   Usage: High   Status: Current
[14.60] Speed Indicator with metric sign applicable to Metro units.
Area: Pelaw - Sunderland (subsequently also Ashford International)   Usage: High   Status: Current

Where an emergency speed restriction exceeded 2 km (1¼ mile) in length, the Rule Book had required the signalman to verbally advise each driver that approached it until such time as they had been informed of the restriction by special advice or notice. This was intended to avoid a situation where a driver assumes he or she has missed the termination indicator (see [14.38]) and accelerates while still inside the restriction. To obviate the requirement for the signalman to verbally advise drivers, special signage was used at Standedge Tunnel on occasions when a 20 m.p.h. emergency speed restriction had to be imposed throughout its entire length (more than 3 miles). In addition to the usual signage, a separate sign worded "tunnel" was exhibited underneath the speed indicator [14.61]. Similar signs were available for use at Morley and Bramhope Tunnels from 2007. The use of these signs at all three tunnels was discontinued in 2008 when a change to the rules removed the requirement for drivers to be verbally advised of the restriction.

[14.61] Speed Indicator with "Tunnel" Sign.
Area: Various   Usage: Low   Status: Historical