Signs in Electrified Areas

The various signs that are installed to give instructions to drivers of electric trains passing through the traction current changeover zones were of the same design as the signs used on the French railway system (SNCF) [18.22 - 18.26]. These signs were installed at Dollands Moor in 1993 in readiness for the opening of the Channel Tunnel, and also between Kensington and North Pole on the West London Line.

For a changeover from AC to DC traction power, another sign marks the position by which the pantograph(s) must be lowered. This sign depicts a pair of solid white shapes, each resembling the cross section of a plano-concave lens, set horizontally against a square black background with a white border [18.23]. The driver may lower the retractable shoegear, and the train may take DC traction power. A subsidiary plate may be fitted showing the voltage type to be selected [18.24] (these are not fitted between Kensington and North Pole).

[18.23] Execute Sign for Lower Pantograph(s). Area:Various Usage: Medium Status: Current	[18.24] Execute Sign for Lower Pantograph(s), with subsidiary plate. Area:Various Usage: Medium Status: Current

For a changeover from DC to AC traction power, a sign marks the position by which the shoegear must be raised. This sign has a similar appearance to the 'lower pantograph' sign described above, but rotated through 90° [18.25]. The driver may raise the pantograph(s), and the train may take AC traction power. A subsidiary plate may be fitted showing the voltage type to be selected [18.26] (these are not fitted between Kensington and North Pole).

[18.25] Execute Sign for Raise Pantograph(s). Area:Various Usage: Medium Status: Current	[18.26] Execute Sign for Raise Pantograph(s), with subsidiary plate. Area:Various Usage: Medium Status: Current

At some locations, an 'abort' board bearing a letter "A" [18.27] 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" [18.28] 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.

[18.27] Power Changeover Abort Board. Area:NR/CTRL Interfaces Usage: Low Status: Current	[18.28] 'Degraded' Board. Area:NR/CTRL Interfaces Usage: Low Status: Current

The electrification system on the West London Line changes from 750 V DC third rail to 25 kV AC overhead wire at North Pole Junction. Passenger services were operated by dual-voltage Class 313 electric multiple units capable of drawing power from either system. Circular boards with the legend "313 units" at the top were installed to mark the location where their pantographs had to be raised [18.29] or lowered [18.30].

[18.29] "Pan Up" Sign. Area:North Pole Junction Usage: Low Status: Current	[18.30] "Pan Down" Sign. Area:North Pole Junction 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. Dual-voltage Class 313 electric multiple units also operated on this line, and boards were installed at each location where their pantographs had to be raised or lowered (Acton Central, Willesden, Camden Road, Dalston Kingsland and Hackney Wick). The boards have a similar appearance to those at North Pole Junction (see [18.29 & 18.30]) but are square in shape [18.31 - 18.33].

[18.31] "Pan Up" Sign. Area:North London Line Usage: Medium Status: Current	[18.32] "Pan Down" Sign. Area:North London Line Usage: Medium Status: Current	[18.33] "Pan Down" Sign (e.g. applicable only to trains routed to No. 2 Line). Area:North London Line Usage: Low Status: Current

In February 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 [18.34]. In the event of flooding, the indication changed to display the words "tunnel flooded" in red letters [18.35]. This indicator lasted until closure of the North Woolwich line in May 2007.

[18.34] Flood Alarm Signal (normal aspect). Area:Silvertown Tunnel Usage: Low Status: Historical	[18.35] Flood Alarm Signal ('stop' aspect). Area:Silvertown Tunnel Usage: Low Status: Historical

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 [18.37]. 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 [18.38]. 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 [25.44 & 25.45]) may be provided for this purpose.

[18.37] Open Circuit Breaker Sign. Area:CTRL Usage: Medium Status: Current	[18.38] Close Circuit Breaker Sign. Area:CTRL Usage: Medium Status: Current

Section 18: Signs in Electrified Areas

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