new Southern Electric Group logo

Three Bridges Signalling Centre 2012

On Saturday 19th May 2012 ten Southern Electric Group members visited Three Bridges Signalling Centre. The Signalling Centre is in the rather anonymous building behind the high galvanised paling fence at the south end of platform 5. We were greeted at the locked gate from the platform by Network Rail's Shift Signaller Manager Ian Semple, who took us to the signalling centre, which is at the south end of the building on the first floor. Upon entering the large airy room we found a calm and quiet atmosphere. The latter was about to change once we started looking around! The east side of the room contains a very large display and operating desk of eight panels for the London-Brighton section, sweeping in a gentle arc almost for the whole length of the room. A more compact display and desk with one panel for a small part of the Mid-Sussex line taken over more recently occupies the south west side and in the centre is a raised supervisory/administration position. The room has subdued general lighting, with large windows overlooking the south end of Three Bridges station, but very effective task lighting at operating positions.

Overview of the Norbury/Norwood Junction to Brighton section The main Norbury/Norwood Junction to Brighton section

photograph by Colin Duff

Ian Semple took us to the Mid Sussex line panel to explain the signalling centre and what the signallers do.

The more recent Mid Sussex line panel the Mid Sussex Line panel

photograph by Colin Duff

Three Bridges Signalling Centre was opened on 25 th June 1983 as part of the £130million "Operation New Look". It uses track circuit block detection and entry-exit route setting. The eight original panels cover Norbury and Norwood Junction to Brighton and Hove , including in their entirety the Caterham and Tattenham Corner branches. Other boundaries are west of Waddon, east of Riddlesdown, east of Godstone, east of Reigate, south of Plumpton, east of Falmer and west of Hove. The Mid Sussex line panel was added in 2005 using the same technology. It covers lines from north of Holmwood to south of Christ's Hospital, and of course to Three Bridges. More of the Mid Sussex line will come under Three Bridges control next year. In a few years' time this signalling centre will be superceded by a new larger IECC facility the other side of the tracks, which will cover a much larger area, including taking over Victoria , London Bridge and West Hampstead boxes' patches.

The signalling centre operates nine panels, 1A - Anerley , Norwood Junction and Selhurst Depot, 1C (split from 1A two years ago)- Norbury to West Croydon, 1B - East and South Croydon station areas, 2 - Purley and branches, 3 - Redhill and part of the Tonbridge line, 4 - Gatwick Airport and Three Bridges, 5 - Haywards Heath and Keymer Junction (with one CCTV level crossing at Keymer), 6 - Brighton and Hove triangle, and finally the new panel for Horsham area including two CCTV level crossings in Crawley.

Panel number 5 - Haywards Heath to Keymer Junction Panel 5 - Haywards Heath to Keymer Junction including the level crossing at Keymer

photograph by Lester Hayes

We were treated to a demonstration of the entry-exit route selection, operation of the level crossing gates near Crawley station and various communications systems. In the case of the latter it was interesting to note that the monochrome cathode ray screen monitors are only live when preparing to lower the barriers and automatically shut off when the barriers are successfully down, although they could be made live manually at any time, which the signaller did to let us see a train pass. We were treated to a demonstration of some of the emergency equipment and the driver of a Mid Sussex service was asked to make a test emergency call.

Detail on the Mid Sussex Line panel detail on the Mid Sussex line panel incluing the tow level crossings at Crawley

photograph by Lester Hayes.

Thereafter we were left to wander around and trusted to ask questions of the signallers without detracting them from their important duties. All signallers were generous with their time and knowledge, for which we are all extremely grateful. We learned that they liked the large display and using real knobs and switches, so were not looking forward to the new IECC's much more automatic computerised technology. They also told us how tricky it was to keep things operating well on a line running close to full capacity, especially on the two track section south of Balcombe Tunnel Junction. A challenge they are facing over the summer is Southern operating a peak service all day seven days a week during the Olympics, plus running the service longer. To my amateur eyes, denoting LOROL services with a 9 prefix clearly distinguished them, but I noted the signallers knew which was what well of by heart anyway, plus if all else fails they have documentation to refer to. Of interest, the platforming arrangements at, for instance, Brighton are pre-ordained by the Station Working Book compiled by Southern, as the station operator, and is only varied by the signaller when responding to an incident.

East and West Croydon displays Display showing East and West Croydon

photograph by Lester Hayes

To become a signaller it takes nine weeks at Signalling School at Leeds. Thereafter it is training on the job under supervision and then later mentoring, starting with less demanding panels and working one's way up with experience. One of the signallers, a middle aged man, described himself as a "mere boy" with only ten year's experience! These days many signallers' only experience of absolute bock working is at Signalling School. Many of the signallers had worked in other boxes previously, including those on the Mid-Sussex line. There is a particularly interested in a display board full of pictures and details of signals passed at danger (SPAD) on their patch. Although a SPAD incident is rarely the signaller's fault it is thought important that they be aware of what the driver sees and the issues at these locations.

Haywards Heath display Haywards Heath

photograph by Colin Duff

Three Bridges works a three shift system, 06:00-14:00, 14:00-22:00 and 22:00-06:00 seven days a week 365/6 days a year. The early and late shifts work with three links covering up to nine operating positions. All signallers get at least an hour's break in the day, incrementally up to two hours if working the more demanding panels. During a shift signallers are rotated between panels and work those panels for durations inversely proportional to the workload they provide. There are fewer on duty overnight and seven night shifts are worked in a row.

Historical artefacts on display Historical artefacts on display

photograph by Lester Hayes

The signallers are supported by Field Operations Managers, who travel around their patch by car if attendance at any site is required. In the case of operating difficulties they are also supported by the combined Southern/Network Rail Sussex Route Control Centre at Southern House, Croydon.

The Brighton Main Line and Mid Sussex Lines diverge, as seen from the signalling centre The Brighton Main Line and Mid Sussex Lines diverging as seen from the signalling Centre

photograph by Colin Duff

Our visit lasted an hour and three quarters and I hope we were not disruptive. We were made very welcome and it was an interesting and memorable occasion for all of us. Therefore we are extremely grateful to Nick Thorley of Network Rail for organising this at their end, Ian Semple and his links of signallers on duty at the time, and to Stuart Hicks for organising us. We raised £55 for Network Rail's nominated charity "Action for Children".

Photographs taken and displayed here with the kind permission of Network Rail.