Section 12: Signs for Train Protection Systems and Cab Signalling

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Around 2006, Arriva Trains Wales trialled AWS reminder boards with an inverted triangular shape [12.32] at certain stations on the Welsh Valley Lines. The signs were installed at the platform ends. Similar signs have subsequently been provided at various other stations, both on and off the Arriva Trains Wales network.

[12.32] AWS Reminder Board. Area: Various   Usage: Medium   Status: Current

The opening of Section 2 of the Channel Tunnel Rail Link in November 2007 saw a return to the provision of AWS boundary signs with black backgrounds (see [12.12 & 12.13]), although the new 'end of AWS' signs have a single diagonal red stripe [12.33]. Note that the letters "AWS" on these signs may refer to the French KVB system rather than the BR AWS system. "KVB" stands for 'Contrôle de Vitesse par Balises', meaning 'Speed Control by Beacons'. KVB was installed on the CTRL approach to St. Pancras International station in 2007 and was later added in the Ashford International station area in 2018.

[12.33] End of AWS. Area: Various   Usage: Medium   Status: Current

From 2009, the train-operated (hydro-pneumatic) points on lines worked by the No-Signalman Token Remote (NSTR) system were being converted to conventional power operation. As this work was carried out, TPWS indicators (see [12.26 & 12.27]) were provided at the stop boards applicable to trains departing a crossing loop in the usual direction. These are in addition to the TPWS indications located inside the token instrument huts.

The European Train Control System (ETCS) is a signalling and train control system developed with the backing of the European Union. ETCS may be overlaid onto ordinary lineside signalling, or alternatively it may function solely as cab signalling. The standard form of block marker for ETCS lines with cab signalling is similar to a TVM block marker (see [12.22]), but the triangle is replaced by an arrow [12.34]. The arrow points towards the line to which the marker applies. In the unusual situation where a block marker is mounted directly over the line to which it applies, the arrow points down [12.35]. The first British application of ETCS cab signalling was on the Cambrian Lines in 2010/2011.

Shunt entry boards associated with ETCS cab signalling are of similar appearance and purpose to the TVM shunt markers on the Channel Tunnel Rail Link (see [12.23]), but auxiliary signals are not provided.

[12.34] ETCS Block Marker (e.g. applies to the line on the right). Area: All Areas   Usage: High   Status: Current	[12.35] ETCS Block Marker applicable to the line below. Area: All Areas   Usage: Low   Status: Current

The stop board protecting the link to the North Norfolk Railway at Sheringham station was provided with a TPWS lineside status indicator in March 2011. The black backboard is labelled with the letters "TPWS" to the right of the blue light [12.36]. Since the TPWS Train Stop System (TSS) loops at the stop board are permanently energised, this indicator is not equipped to show a flashing indication.

[12.36] TPWS Indicator. Area: Sheringham   Usage: Low   Status: Uncertain

In June 2013, experimental signs were installed at certain locations on the London, Tilbury & Southend line to denote the presence of TPWS Overspeed System (OSS) loops. Each sign comprised a white inverted triangle with the letters "TPWS" in black. A sign associated with a signal OSS had a red border [12.37], and a sign associated with a permanent speed restriction (PSR) OSS had a yellow border [12.38]. The boards were manufactured with the applicable set speed (the speed below which a train must pass to avoid a TPWS intervention) displayed in the centre, but this information was initially covered over. The set speeds on the signs associated with PSR OSSs were subsequently uncovered [12.39], and a number of similar installations were made at various locations around the Anglia Route. Informing drivers of the set speed prompts them to check their speed and enables them to decelerate slightly if necessary, to avoid an unexpected TPWS intervention.

[12.37] TPWS Sign associated with a Signal OSS. Area: LT&S line   Usage: Low   Status: Historical	[12.38] TPWS Sign associated with a PSR OSS. Area: LT&S line   Usage: Low   Status: Historical	[12.39] TPWS Sign associated with a PSR OSS, showing the set speed (e.g. 69 mph). Area: Anglia Route   Usage: Low   Status: On Trial

The triangular type of AWS reminder board (see [12.32]) may have the number of the next signal beyond stated at the top [12.40].

[12.40] AWS Reminder Board. Area: Various   Usage: Low   Status: Current

The Crossrail Central Operating Section, which opened in March 2021, has a form of cab signalling called Communications-Based Train Control (CBTC). The block markers for CBTC have the same appearance as those used for TVM cab signalling (see [12.22]). Signs denoting the start and end of CBTC cab signalling are similar to the standard signs for start and end of cab signalling (see [12.14] and [12.21]), but the word "cab" is replaced by the letters "CBTC" [12.41 & 12.42]. The system of cab signalling is specified on these signs to take account of trains transitioning to and from areas with ETCS cab signalling.

[12.41] Start of CBTC Cab Signalling. Area: NR/Crossrail Interfaces   Usage: Low   Status: Current	[12.42] End of CBTC Cab Signalling. Area: NR/Crossrail Interfaces   Usage: Low   Status: Current