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Section 18: Signs in Electrified Areas

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At some locations, an 'abort' board bearing a letter "A" [18.25] may be placed ahead of a traction current changeover zone. This sign applies only to Eurostar drivers. If the changeover has not been successfully completed by the time the front of the train reaches this sign, the train must be brought to a stand and the driver must examine the train. Alternatively, a 'degraded' board bearing a letter "D" [18.26] may be placed ahead of a changeover zone. If the changeover has not been successfully completed by the time the front of the train reaches this sign, the driver must advise the Route Control Centre of the exact status of the train and stop at a location where assistance may be rendered.

[18.25] Power Changeover Abort Board.
Area: NR/CTRL Interfaces   Usage: Low   Status: Current
[18.26] 'Degraded' Board.
Area: NR/CTRL Interfaces   Usage: Low   Status: Current

In 1996, the electrification system on the part of the North London Line between Acton Central and Camden Road was altered from 750 V DC third rail to 25 kV AC overhead wire. Passenger services were operated by dual-voltage Class 313 electric multiple units capable of drawing power from either system. Boards were installed at each location where the pantograph has to be raised or lowered (Acton Central, Willesden, Camden Road, Dalston Kingsland and Hackney Wick) [18.27 - 18.29]. In recognition of the introduction of Class 378 EMUs in 2009, later examples of these signs bear the legend "313/378 units" at the top.

[18.27] "Pan Up" Sign.
Area: North London Line   Usage: Medium   Status: Uncertain
[18.28] "Pan Down" Sign.
Area: North London Line   Usage: Medium   Status: Uncertain
[18.29] "Pan Down" Sign (e.g. applicable only to trains routed to No.2 Line). Click Here for Photo
Area: North London Line   Usage: Low   Status: Uncertain

In 2002, the one remaining flood alarm signal at the east end of Silvertown Tunnel (see [18.14 & 18.15]) was replaced. The new indicator normally displayed a solid white rectangle [18.30]. In the event of flooding, the indication changed to display the words "tunnel flooded" in red letters [18.31]. This indicator lasted until closure of the North Woolwich line in 2007.

[18.30] Flood Alarm Signal (normal aspect). Click Here for Photo
Area: Silvertown Tunnel   Usage: Low   Status: Historical
[18.31] Flood Alarm Signal ('stop' aspect).
Area: Silvertown Tunnel   Usage: Low   Status: Historical

On the high speed lines (from 2003), signage associated with a neutral section mirrors French practice. The first sign encountered by drivers is a warning board stating the distance to the neutral section, in metres [18.32].

[18.32] Warning Sign for Neutral Section (e.g. 400 metres ahead).
Area: CTRL   Usage: Medium   Status: Obsolescent

A sign positioned on the approach to, and close to the neutral section marks the point by which the main circuit breaker on the traction unit should have been opened [18.33]. If this has not occurred automatically, the driver should open the circuit breaker manually. Beyond the neutral section is a sign to indicate the point where the driver can reclose the main circuit breaker, if it has not occurred automatically [18.34]. If the train has more than one locomotive or power car in operation, the rearmost vehicle should have passed the sign before the circuit breaker is closed. An 'end of restriction' marker (see [25.37 & 25.38]) may be provided for this purpose.

[18.33] Open Circuit Breaker Sign.
Area: CTRL   Usage: Medium   Status: Current
[18.34] Close Circuit Breaker Sign.
Area: CTRL   Usage: Medium   Status: Current

In 2004, work was under way to upgrade the traction power supply between Earlswood and Three Bridges. In the event of an electrical disruption occurring while this work was taking place, it was necessary for drivers of Class 375 and 377 'Electrostar' units to drive in Notch 2 through the substation area affected. When these circumstances applied, special temporary signs would be displayed at the beginning [18.35] and end [18.36] of the affected area. In certain locations, one sign applied to the tracks on either side, indicated by arrows pointing left and right [18.37 & 18.38].

[18.35] 'Notch 2' Commencement Sign.
Area: Southern Region   Usage: Low   Status: Historical
[18.36] 'Notch 2' Termination Sign.
Area: Southern Region   Usage: Low   Status: Historical
[18.37] 'Notch 2' Commencement Sign.
Area: Southern Region   Usage: Low   Status: Historical
[18.38] 'Notch 2' Termination Sign.
Area: Southern Region   Usage: Low   Status: Historical

Later in 2004, signs similar to [18.35 - 18.37] were provided in connection with power supply upgrade work between Herne Hill and Sydenham Hill. These signs applied to 'Electrostar' units of Classes 375 and 376 and therefore had the legend "375/6" at the top.


Later examples of neutral section warning boards on the Channel Tunnel Rail Link [18.39] differ slightly from the earlier type (see [18.32]).

[18.39] Warning Sign for Neutral Section (e.g. 1000 metres ahead).
Area: CTRL   Usage: Medium   Status: Current

On the Channel Tunnel Rail Link, a diamond shaped sign [18.40] denotes a location where the overhead catenary wire ends. Electric trains must not pass without the pantograph first being lowered. This sign is of similar style to those used on German Railways (Deutsche Bahn) for the same purpose.

[18.40] 'Limit of Electric Traction' Sign.
Area: CTRL   Usage: Unknown   Status: Current

In 2011, new rules were introduced to permit electric trains to coast at high speed, with their pantographs lowered, through a section where the power to the overhead line equipment has been isolated because of damage, power failure or planned engineering work. Temporary 'lower pantograph' and 'raise pantograph' signs (see [18.21 & 18.23]) will be provided at the beginning and end of the affected section. In addition, an 'advance lower pantograph' sign with two flashing white lights [18.41] will be placed about 400 metres on the approach to the 'lower pantograph' sign and a 'do not raise pantograph' sign [18.42] will be placed beyond the 'raise pantograph' sign. If the pantograph has not been raised by the time the train reaches the 'do not raise pantograph' sign, the pantograph must not be raised until the speed of the train has been reduced to 20 m.p.h. Before allowing an electric train to approach an affected section, the signalman will verbally advise the driver that high speed coasting is taking place.

[18.41] 'Advance Lower Pantograph' Sign.
Area: All Areas   Usage: Medium   Status: Current
[18.42] 'Do Not Raise Pantograph' Sign.
Area: All Areas   Usage: Medium   Status: Current