The major routes of the old London Brighton & South Coast Railway have been resignalled many times since the company went out of existence in 1923. However the secondary routes, although mainly electrified many years ago, retained their traditional signalling right up to the present day with lever frame boxes and semaphore signal arms.
Now many decades old and well beyond normal life expectancy, the time has come to bring these routes into the digital age and control them from the Three Bridges Rail Operating Centre (ROC). The first such route to be converted is in East Sussex between Lewes and St Leonards. This section of line caused some interesting challenges with the many level crossings that needed upgrading along the way.
The route Lewes is a four-way railway junction: to the west are the lines to Brighton and Wivelsfield, which were resignalled in the early 1980s with Lewes becoming the fringe box to the then brand new Three Bridges Power Box. To the east are the lines to Newhaven / Seaford and to Eastbourne / Hastings. Eastbourne underwent a signalling upgrade in 1992 to replace the mechanical signalling in the immediate station area and introducing a Solid State Interlocking at that time with colour light signals.
The East Sussex scheme extends from Southerham Junction, where the Newhaven line diverges, to the charmingly-named Bo Peep Junction at St Leonards where the main route from London to Hastings is joined.
The Newhaven line remains with traditional signalling for the present. Lewes remains as a fringe box to both Three Bridges PSB and the new signalling, with Bo Peep being the fringe at the eastern end.
The mechanical boxes removed from operational service are: Berwick, Polegate, Hampden Park and Pevensey & Westham, together with a gate box at Havensmouth (Normans Bay). Although Eastbourne box has closed, the interlocking is now re-controlled from Three Bridges ROC. The overall distance is around 25 miles. The project and technology Network Rail has its own internal mechanism for producing the business case to justify the necessary investment.
The commercial scheme sponsor is Tony Hescott from the operations group and it has been his role to determine the scope of the project, to gather all the costs together and to then take the scheme forward for authorisation. This process began in 2010 and was one of the first re-signalling projects to be undertaken in this manner. The project value worked out at £40 million which, as well as being renewal driven, will yield significant staff savings and increased line capacity. The internal sponsor then contracts the work to the Network Rail projects group to take the project forward from detailed design to commissioning. Huw Edwards assumed this responsibility at a late stage of the project but nonetheless took it through to completion.
The overall project contract was let to Atkins as one of the three nominated Network Rail suppliers for major signalling schemes. Atkins has the internal expertise to do all the design and management activities but does not have a manufacturing capability, so the supply of the necessary hardware was therefore contracted to a variety of signalling companies.
- Interlocking equipment at the ROC – conventional solid state interlocking supplied by Signalling Solutions Limited;
- ROC signaller’s control panel screens – GE Transportation Systems (GETS); » Lineside signals – Dorman;
- Point mechanisms – existing mechanical, HW point motors, old style clamp locks and one set of spring points, all replaced by In Bearer Clamp Locks either during previous stageworks or at the main commissioning;
- Axle counters – Frauscher;
- AWS and TPWS – free issue from Network Rail;
- Level crossing booms and barrier machines free issued from Network Rail via SPX;
- Level crossing obstacle detection equipment free issued by Network Rail via TEW;
- Level crossing road traffic signals obtained from Unipart Rail.
The colour light signals are of the LED type but are mounted on lightweight posts that can be lowered to facilitate ease of maintenance. Axle counters have replaced track circuits to aid reliability. Installation of the civils element was entrusted to BCM and TPWS has been fitted to the signals judged as critical in terms of SPAD occurrence.
The line speed from Southerham to Wilmington has been raised to 90mph from 70/80, and the signals are positioned for this speed through to Bo Peep Junction although the speed increase on this section is not yet implemented as the civils work needed is beyond the current contract scope. The basic track layout remains unchanged except for the removal of some crossovers.
To distribute the information from the ROC to the individual lineside elements, use has been made of the Network Rail Telecom FTN transmission capability. This provides a dual resilient link to every lineside module such that if any one cable should be cut, the system can still operate via the alternative route. The acceptance by the signalling fraternity of the use of the FTN has been a big step forward psychologically as not only does it give improved reliability, it enables significant saving to be made on cabling.
Since all of the Cab Secure Radio network in the south of England had been replaced by GSM-R a while ago, the radio infrastructure already existed. Control of the track-to-train voice communication had, however, to be transferred to Three Bridges ROC where new radio panels are provided for the relevant signaller.
These abound on this section of line and new means of control has been adopted for many of them. The new technology of obstacle detection (OD) to facilitate the semi-automation of four barrier-controlled crossings was appropriate for a number of them.
Obstacle Detection (OD) level crossings were originally introduced on the Ely-Thetford – Norwich line. They are essentially an alternative technology to manual surveillance of a four-barrier crossing, remotely controlled by a signaller using CCTV pictures to verify the crossing is unobstructed before clearing the controlling signals. The application of OD simplifies this process and once the detection confirms that no obstacle is present and the barriers are down, the controlling signals can be cleared automatically.
The detection equipment is a combination of RADAR and LiDAR technologies. RADAR (Radio Detection and Ranging) is well proven and has equipment mounted at a high level to detect any general movement on the crossing. LiDAR is newer and is there to detect any low level object that might be missed by RADAR.
Significant problems have emerged as LiDAR requires a laser light beam to be sent from a transmitter to a receiver on site. If this beam cannot be detected, then the fail safe nature of the operation will prevent the LiDAR from confirming the crossing is clear. Being situated at low level, the equipment was subject to spray and dirt being thrown up by passing trains, thus causing a failure. As one person said, the only solution was to have someone on hand constantly with a packet of baby wipes!
Reliability has been key and various trials have established that the ground level LiDAR can be dispensed with, leaving an upper LiDAR, around a metre high, to supplement the RADAR detection.
As can be imagined, this change has required significant safety analysis, verification and acceptance and has been the prime reason why the East Sussex re-signalling date had to be put back from its original 2013 introduction. The safety case has now been duly signed off and should allow OD-protected crossings to be applicable to all other areas of Network Rail. A unique crossing situation was present at Havensmouth (Normans Bay). This was a manned, gated hand-worked crossing which required the duty gatekeeper to manoeuvre the gates across a private road. The operative then operated the switch panel which released the signalled slot to allow the signaller at Pevensey & Westham to set the route for the safe passage of trains over the level crossing.
In order to protect the private road status, the gates were locked up by the operative between 21:55 and 06:55 hours (on a daily basis) which prevented vehicle access during this time. Under this arrangement, one of the land owners had an arrangement whereby contact would be made with the gatekeeper to lock the gates in the event of transferring live-stock across the private road (on the north side only) from one field to the other. This provided ‘the protection from the railway’ requirement to reduce the risk to ‘as low as reasonably practical’ (ALARP) from livestock gaining access onto the level crossing.
As a result of the introduction of the new MCB-CCTV level crossing at this location, with the barriers normally in the raised position except when trains are due, the scheme sponsor had to investigate options to maintain and replicate the safe status.
The solution adopted was:
- The installation of yellow secondary gates (on the south side) to provide the facility for residents to close the road in order to support maintaining the private status. Pedestrian access is available via an offset gap.
- The installation of a yellow swing arm gate (on the north side), to provide a similar facility for the private road to be closed by the residents, at their discretion. Note that this is a different design to the above to fit with road width constraints. Pedestrian access is maintained by a corral gate at the side.
- The installation of metal-framed gates on each side of the private road which open and meet in the middle, thus permitting the safe transit of live-stock from field to field and preventing access to the railway if the new barriers are raised. This satisfies the ALARP status.
- The installation of the appropriate signage. To achieve this somewhat unusual solution, the Network Rail scheme sponsor had to undertake a significant amount of stakeholder management/negotiation activity with the land owners and residents of Normans Bay.
Remote condition monitoring
The opportunity has been taken to use the computer equipment in Three Bridges ROC to apply remote condition monitoring on critical pieces of external equipment. These include clamp locks, level crossing barrier machines, axle counters, power supplies and building security. As well as providing alarms for when failures occur, the performance of the equipment is monitored against a set of parameters such that any significant deviation from the norm can be detected and pending problems put right before an actual failure occurs.
Most of the implementation work was carried out during weekend possessions, the only blockade being needed for the commissioning weekend on the 13/14/15 February 2015 covering the period from the last train on Friday to early Monday morning. All went to plan and the first train left Eastbourne on time at 05:08 on the Monday in readiness for the weekday commuter traffic. Buses were kept on standby just in case but were not needed. Since then, the system has worked reliably and no problems of any significance have occurred.
There is an East Sussex re-signalling stage 2 project in progress to cover the Newhaven branch and the final elimination of the old box at Lewes. This will take place during the CP5 period probably some time in 2019.