For the last six years, Network Rail has staged nine one-day seminars with suppliers from the signalling industry to brief them on the engineering and technical developments that are taking place and to get feedback on the issues seen as pertinent. The 2012 event took place recently in Glasgow, so the rail engineer ventured north of the border to sit in on the discussions.

In opening, Mark James, the head of Engineering Signalling in Network Rail, recalled that the company has now been in existence for ten years and, in that period, much has happened in the way the rail infrastructure is managed with many implications for signalling.

The concept of a ‘Signalling Industry Partnership’ has come about and, in Control Period 4, 9,300 Signalling Equivalent Units (SEUs) have been renewed, 2,400 SEU re-locks or re-controls have happened and 1,500 SEUs are now commissioned using the new modular technology. However, signalling costs are still considered to be too high and a real reduction of 16% is the target by 2019. The ‘cradle to grave’ time to develop and implement signalling projects is far too long; the Network Rail chairman has been surprised by the old methods used in the signalling profession. Hopeful signs are there to get practices modernised: plug and play cabling, lightweight signals, signals on OLE structures, 3D mapping, paperless testing, intelligent scheme plans. Acceleration in project delivery is the first priority; innovation and new technology will be secondary to this.

Power distribution and cable types

Signalling systems require reliable power supplies, both in equipment rooms and at the lineside. A new generation of trackside power units – switchgear, transformers and distribution units – has emerged in recent times to complement the predicted growth in new signalling schemes. The increase in power demands can probably only be achieved from an extended supply chain.Image1 [online]

A major part of power provision is the associated extensive cable network. Traditionally, this has been copper based, an increasingly expensive metal. Some reduction in need has been achieved by using two instead of three-core cable, as is reported in our previous issue, but replacing the expected demand for one million kilos of copper with something else is the challenge.

The solution, according to Tahir Ayub from Network Rail, is aluminium. This is an abundant metal that is theoretically 100% recyclable without loss of characteristics. It is £2,000/tonne compared to copper at £8,000/tonne, but needs a bigger core size for the same conductivity. Nonetheless, a saving of £8.50 per metre is possible giving a saving of around £400,000 per project.

Downsides are few: location cases will need some re-design as the cable is harder to bend and an increase from 650V to 1000V for the main signalling distribution feeders might be necessary. In addition to cost reduction, there are considerable other advantages. Using a stranded cable, unarmoured but with a jelly fill, will yield a huge reduction in weight thus permitting bigger drums and more hand pulling. Bolted rather than compression terminations are coming out as favourite. The business and technical case is in preparation and looks promising. Equally, signalling equipment designers can help by removing peak load surges, point machine design being a good example.

Records, drawings and data

The acquisition, processing and retention of records and other data has always been a challenge for railway engineers, and signal engineers in particular. Laborious, paper-based information was for long the order of the day and even the introduction of CAD tended only to replicate the paper procedures that had gone before. It is evident now, however, that much more imaginative use of computers could thoroughly modernise these outdated methods.

Signalling scheme plans are one such example and Ken Peters from Network Rail described how the Signalling Tools and Method Programme (STAMP) is revolutionising the production of such plans. Begun in 2005, the system has now matured and trial usage has been in place since 2010. The programme focuses on the structure of asset data rather than producing drawings by capturing the detail of a 3D design within a geo-spatial cross-disciplinary approach which models and simulates the working railway environment. Such designs are to use a common Signalling Data Exchange Format (SDEF) that will eventually become mandatory. The concept of automatic image recognition using video collected from a track recording unit in the Cardiff area has been trialled, and from this information new assets can be inserted into the resultant maps.

Once it has been collected, validating SDEF data needs computer-aided assistance. Jennifer Whittlesea from Selex explained how a self-contained website application can be used which allows the processing of SDEF XML files including the conversion if they were created in different versions. From this, the system will determine whether an SDEF design is valid for its intended new application. Examples are the headway analysis tool that will look at intended train service patterns and a facility to see if existing rules for scheme plans are pertinent or relevant. From all of this, asuiteofrulescanbebuiltupbyuseofa graphical editor.

Collecting data is one thing, controlling access to it is another challenge. Eddy Locke, from Network Rail’s data collection services, explained some of the considerations that must take place. To ensure data quality, the following tests have to be fulfilled: does the data have an owner, can the data be maintained, who collects the data, how is it collected, and how accurate is it?

Thirty-five terabytes of data are collected each year from various sources including the measurement trains, radio surveys and
manual methods. The Network Rail data centre at Milton Keynes is upgrading its storage capacity to 140 TB but the key will
be to analyse, decide on relevance and distribute data to the right people. The ORBIS project (as mentioned in issue 98, December 2012) is part of this. As well as being better informed, the project will reduce the number of staff required out on the track, give greater assurance on asset safety condition, and lead to faster remedial work when problems are detected, e.g. broken rails.

Class 158 fitted with ETCS.

Class 158 fitted with ETCS.

Paperless testing

The time honoured way of testing new signalling installations, with its multiplicity of drawings and paper tick sheets, is in need of modernisation. Neil Porter from Atkins explained how this can be achieved – not by altering the process of testing but the way in which it is recorded.

A tester is provided with a mobile device onto which are downloaded the test sheets and test logs. Structured on a central Atkins WAN (wide area network), ‘bluebeam’ software will open up the relevant drawings on the device including all the normal tester ‘marks’ that would expect to be found. The testing activity takes place in the usual way after which the drawings are ‘flattened’ to roll up all the tester’s marks into a pdf file. The files are sent to the original design house from which a new set of task sheets will be prepared by a tester in charge, who will continually review the test sheets to assess progress and credibility. From the revised test logs, the tester can determine the extent of any re-test after which the logs are updated and final test certification achieved.

The process has been successfully tried on a number of small schemes with minor problems of software compatibility identified. Use is intended for both in-house and agency testers. It is, however, dependent on good communications to the test site as well as a robust IT system to ensure continuity of data. Hourly updates of data from WAN to LAN (local area network) would be good practice.

‘Plug and Play’

The idea of having pre-formed cables which can be plugged together and into equipment terminations is attractive as it can save many man hours in the task of cable installation. But is it practical? Graham Thompson described the setting up of a trial site at Leicester that can simulate real trackside conditions. Cable routes, undertrack crossings, power cubicles, main and shunt signals and 2 & 3 door location cases, all replicating a typical signalling installation, have been provided.

Pulling the plug-coupled cables through an undertrack crossing is the biggest worry, especially if they are already in use and partly filled. Nonetheless, the trial has proven the concept. Key will be the accurate measurement of the plug coupled assemblies which have to be precisely the right length. Installation time is significantly reduced and signalling projects can be expected to call for this technology in the future.

Level crossings and obstacle detection

Despite the extensive usage of AHB and AOCL level crossings, a significant number of controlled barriers exist on the UK rail network. Many of these utilise CCTV surveillance so that the signaller can check the crossing is not obstructed before the approach signal is cleared. Can the surveillance task be automated?

It fell to David Jones from the Network Rail signal design group at York to describe how obstacle detection technology can achieve this. Two detection systems are required – RADAR (radio detection and ranging) and LIDAR (light detection and ranging). The RADAR needs detectors at each of the crossing corners to provide reference points for the four RADAR sensors.

These will provide a continuous‘picture’of the crossing and can compare to the reference. However, RADAR cannot scan down to ground level and would miss a person lying down. Thus the LIDAR system is also employed using both high and low beam scanning lasers. Two LIDAR units are required, oriented towards each other.

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Photo: Unipart.

In operation, the strike-in point is at the signal showing green before the crossing control signals, whence the entrance barriers (the left hand ones) will lower. If the obstacle detection system then determines the crossing is clear, the exit barriers (the right hand ones) will lower. If, however, an obstacle is detected, the exit barriers are held for a further ten seconds. In the event that, after this period, an obstacle is still detected, then the barriers will lower but the controlling signals will not clear. The exit barriers will then be raised again to allow anything trapped to escape. This sequence continues and only when an obstacle is no longer detected will the signal clear. Video cameras and recorders will monitor the events, these having number plate recognition equipment and backed by inductive loops in the roadway to identify rogue road users.

Three such crossings have been installed as a trial between Ely and Norwich as part of the modular signalling project and further installations between Crewe and Shrewsbury and at Llanelli were in place by the end of 2012. Training courses are in preparation and signalling installation and testing manuals are being updated. A framework supply contract is in the offing. This looks like being a standard feature for such crossings in the years to come, thus saving the cost of conventional CCTV installations and signaller time.


The Network Rail update on progress with ERTMS, as given by Carine Marin, came across as very positive but perhaps somewhat over- optimistic. The Cambrian ‘early deployment scheme’ (in other words – a trial) is now fully operational and many valuable lessons have been learned. The claim that ERTMS will yield lots of extra capacity has yet to be borne out and it must be remembered that other, more modern designs of train control system have emerged since the development of ERTMS commenced nearly twenty years ago. The biggest on-going constraint is the lack of data capacity on the GSM-R bearer and experience in Europe has shown that the system is incapable of being used in high traffic areas such as big terminal stations.

The radio problem is one that needs to be addressed urgently at a European level and, whilst the solution of moving to 4G is often advocated by the mobile radio industry, no practical solution has yet emerged as to how this would be achieved in practice on an operational railway. The migration path from GSM-R and the avoidance of huge amounts of additional cost need to be part of any plan.

Network Rail would be well advised to critically examine their ERTMS promotional video and re-format it so as to give a realistic forecast on what ERTMS can and cannot do. Raising expectations that turn out to be false could lead to severe embarrassment at a future date.

Other initiatives

DeltaRail continued its promotion of IECC Scalable and its first deployments at Cambridge (for the Ely – Norwich scheme) and at Harrogate. A full account of this latest control centre product using message broker technology was given in issue 92 (June 2012) and it looks to have a big future on Network Rail and elsewhere.

The work of the Railway Industry Association was described by Francis How, its technical director and currently the IRSE President. Now 135 years old, the RIA is a trade organisation with a whole range of members – big, small, specialist and general. It sees itself as being supportive to Government, Network Rail, LUL, TOCs, Roscos and others on projects, but additionally promoting innovation, export, skills development, standards evolution and safety policy. The forthcoming rail technical strategy focussing on the 4Cs (cost, capacity, customers and carbon) might equally well apply to careers, competence, capability and collaboration, and the RIA would wish to be at the forefront of all these.

Altogether, a fascinating day where all the suppliers present will have learned something. Network Rail should be congratulated that it takes the time and trouble to brief the signalling supply industry on the latest developments and to encourage co-operation in the sector. Equally, it should be mindful of the feedback it receives from events like this and be prepared to make changes where it would be beneficial to do so.