Section 23: Signs applying only to Engineering Trains or Test Trains

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The signs described in this section are applicable only to specific types of engineering trains, or to trains undergoing tests. These signs must be disregarded by drivers of ordinary trains.

The Advanced Passenger Train (APT) was a tilting train introduced by British Rail in 1979 for West Coast Main Line services. Its tilt system enabled it to travel at higher speeds than conventional trains over curved sections of track. Ultimately, these higher speeds would be continuously indicated to APT drivers on a cab display by a system called C-APT (Control APT). For the duration of the tests which commenced in 1979 however, special lineside marker boards were affixed to electrification structures, between Carnforth (London Midland Region) and Glasgow Central (Scottish Region) via Beattock. Signs were provided at the commencement of the special permissible speeds [23.1] and at the braking point where the permissible speed is reduced [23.2].

[23.1] Commencement of indicated permissible speed for prototype APT.	[23.2] Braking point for indicated lower permissible speed ahead for prototype APT.

Further lineside marker boards were provided in 1981 in association with testing of the APT [23.3 & 23.4]. The APT was withdrawn from passenger service in 1985.

[23.3]	[23.4]

'Sandite' is a substance that can be applied to the rail head by a special train at locations prone to poor adhesion. Lineside markers were installed to assist the staff on board the Sandite train in locating the sites concerned. The first sign, an upright yellow rectangle with three black diagonal bars [23.5] gives advance warning of a Sandite application site. This marker is followed by similar yellow boards with two and one bars at the points where application should begin [23.6] and end [23.7], respectively.

[23.5] Advance warning of Sandite application site.	[23.6] Commencement of Sandite application site.	[23.7] Termination of Sandite application site.

Although it is not a standard sign, a yellow marker with a letter "P" [23.8] is provided at some locations to denote that the application of Sandite is prohibited.

[23.8] Sandite Prohibition Marker.

In 1998, small blue markers [23.9] were installed on the approaches to Theale, Midgham and Thatcham stations (Great Western Zone). These markers were for guidance during braking tests on Class 165/166 ('Turbo') trains.

[23.9] Turbo Braking Trials Marker.

In 1989, lineside markers were installed at certain locations on the Scottish Region applicable to Civil Engineer's staff on the Ultrasonic Test Train [23.10]. These signs are installed at geographical junction locations, adjacent to the facing points, and act as a designated datum point.

[23.10] Ultrasonic Test Train Marker (Scottish Region).

From 1992, lineside marker boards were installed at Sandite application sites on the Scottish Region. The standard Sandite marker boards (see [23.5 - 23.7]) are not used in Scotland. Instead, octagonal boards are provided to denote the commencement [23.11] and finish points [23.12] of the portion of line over which Sandite requires to be applied. No advance warning boards are provided on the approaches to the sites concerned.

[23.11] Commencement of Sandite application site (Scottish Region).	[23.12] Termination of Sandite application site (Scottish Region).

A company called 'LaserThor' developed a system for removing rail head contamination using lasers. A number of trials were conducted, latterly with the laser equipment being mounted on a Multi Purpose Vehicle (MPV). In the autumn of 2003, trials took place at Oxshott and Wanborough on the Southern Region. Signs were installed at each test site to assist the MPV operator. A sign reading "Laser On" [23.13] marked the start of the test site. This was followed by signs lettered "A", "B" and "C" [23.14] at intervals of a quarter mile. The last board in the series, worded "Laser Off" [23.15], was located one mile from the start of the test site.

[23.13] "Laser On" Sign.	[23.14] Intermediate Signs.	[23.15] "Laser Off" Sign.

Leaf residue on the rail head can be removed by high-pressure water jetting. On the Scotland Territory, boards were installed from 2006 at the commencement [23.16] and termination points [23.17] of locations where water jetting is carried out.

[23.16] Commencement of Water Jetting site (Scotland Territory).	[23.17] Termination of Water Jetting site (Scotland Territory).

During the autumn of 2006, marker boards lettered "A", "B" and "C" [23.18 - 23.20] were provided between Ockley and Warnham (Southern Territory) for autumn measurement testing. These signs concerned both the notified MPV treatment train and the Southern test train but with different meanings applying to each. To the treatment train, the "A" marker board [23.18] indicated the point where the notified test specific treatment should be applied. The "B" marker board [23.19] was disregarded by the treatment train, and when the "C" marker board [23.20] was reached, it returned to its usual treatment diagram. For the test train, the "A" marker board [23.18] meant "prepare to conduct brake test". A full service brake application had to be made when the "B" marker board [23.19] was reached. The "C" marker board [23.20] did not apply to the test train.

[23.18] "A" Marker Board.	[23.19] "B" Marker Board.	[23.20] "C" Marker Board.

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