Controlling the electrified railway

There are continued calls for more of Britain’s railways to be electrified in order to improve traction efficiency and meet carbon footprint reduction targets. We are well behind the rest of Europe in increasing the percentage of electrified lines. The reasons for this are many, but electrifying lines is expensive and usually depends on government funding. As is well documented, there has been a reluctance to commit to a rolling programme of electrification because of the high cost, with carbon reduction targets forever being pushed back.

One aspect of electrification, which is often overlooked, is how it is controlled to ensure safe operation and safe isolation for maintenance. Electric trains require electricity to move so the electric current supply must always be available. This means continuous monitoring, remote management and resolution of incidents, fast and safe deployment of patches and fixes, plus a system reference model to be available to test things out before deployment. All of this implies an expensive investment involving 24-hour coverage and skilled manpower.

Can this activity be modernised and made more efficient? An ongoing contract let to Telent is geared to achieving just that.

History and modernisation

Electric Control Rooms (ECRs) are used to control the power supply to an electrified railway. Communication and data links connect these to:

• Feeder stations where power from the National Grid and Distribution Network Operators (DNOs) is transformed and fed to the overhead catenaries for the 25kV energised lines.
• Substations from where AC feeders are transformed and rectified to provide DC for the third rail 750V routes.

Typically, the 25kV feeder stations are around 40km apart and are positioned where high voltage pylon lines cross or are close to the railway. Intermediate switching stations – Track Section Cabins (TSCs) – exist halfway between feeder stations to enable different lines to be switched off for maintenance purposes.

Because the traction current is much higher on the DC network, the substations must be much closer together and it would not be practical to take power from the grid at all of these. This necessitates the provision of a supplementary railway based AC ‘mini grid’ which provides power to substations that do not have an onsite grid connection. The ECRs control the substations together with intermediate ‘track paralleling huts’ that enable power to be switched off from individual tracks when maintenance work is carried out either on the track itself or the third rail.

It is therefore clear that the ECRs have a very important role. There are currently 14 of them covering England, Scotland, and Wales. Six relate to the 25kV AC lines – Romford, York, Rugby, Crewe, Cathcart, and Didcot; Eight control the 750V third rail DC lines – Lewisham, Selhurst, Raynes Park, Eastleigh, Brighton, Paddock Wood, Canterbury, and Sandhills, the latter for the Merseyrail DC network. Various types of equipment exist for the control activity, many from different manufacturers with different man-machine interfaces dependent on the age of the technology.

Some 10 years ago, it was decided that modernisation should take place to produce a unified design for the ECR operation and to have a centralised management centre that could oversee all the ECR assets.

SCADA and TPCMS

The project embraced Supervisory Control and Data Acquisition (SCADA) principles which is a general acronym for industries that have to control many outstations, be it water, electricity, gas, and suchlike. This project has the specific title of TPCMS – Traction Power Centralised Management System.

Telent was awarded a contract in 2013 to provide a single unified electrification control network for the main line railways of Britain. This would replace the existing equipment at the ECR sites, the provision of new communications links using the Network Rail Telecom (NRT) FTNx IP based network, the design and supply of new screen based Graphical User Interfaces (GUIs) at the ECRs, the provision of new Remote Terminal Units (RTUs) at the individual substation and switching locations, plus two data management centres located at Manchester and Three Bridges for overall monitoring of the electrification network.

The contract covers all the existing ECR areas of control except for Didcot which came on stream at a later date as the Great Western electrification was gradually commissioned. It is hoped that Didcot will become part of the overall system in due course.

As well as all the new communications and data links, the contract required the design of the new hardware and associated software. At Telent’s headquarters near Warwick, a reference system would be built to test out the new design and also to serve as a digital twin.

Challenges and progress

It was originally envisaged that the project was scheduled for completion by 2018 but early on it was recognised that this was a much more difficult contract in terms of the work content originally envisaged. All ECRs (Didcot excepted) will be converted to the new system with relocation to Railway Operating Centres (ROCs) being planned in some areas, whilst elsewhere control will remain at existing sites in refurbished facilities.

The connectivity of the two data centres to the ECRs and from the ECRs to the substations and switching locations will, as stated, use the FTNx network which offers high capacity, secure and resilient bandwidth for IP-based applications. It means that every ECR site and outstation will require an IP address. Typically, 100MBits is made available to each RTU site. However, where the transmission to a substation site was reasonably modern, the original ‘pilot’ circuits have been retained but design work has been needed to adapt this connectivity to the new control arrangements.

Creating the software for the project has been more challenging than originally thought and Telent recognised that additional assistance from a specialist company would be required. This was provided by Morson Projects Ltd (MPL), a company headquartered in Manchester with a pedigree of control system design for a range of companies in the defence, infrastructure, and transport industries.

Telent developed the TPCMS software up to v3.2.3 which was fully commissioned and brought into service at both the data management centres in Manchester and Three Bridges along with the ECRs at Raynes Park, Canterbury, Paddock Wood, Selhurst, Romford, and Sandhills.

However, shortfalls in some of the software functionality and overall stability lead to Telent engaging MPL to develop the next iteration of the TPCMS software. V5.0 has subsequently been developed and tested with Raynes Park being the first recipient.

The design of V5.0 has been a collaboration between Telent, MPL, and Network Rail, with the outcome being a baselined version of software capable of being rolled out to all the remaining areas. Both Canterbury and Brighton have been equipped to the new V5.0 software and the rest of the sites will be upgraded over the next nine months.

An important element of any data network these days is cyber security, principally to protect the data from external attacks. The V5.0 software follows the latest standards with penetration testing having taken place successfully. With security built in as part of the requirement, this includes physical aspects such as intrusion alarms, door locks, and suchlike.

The remaining legacy ECR sites will employ V5.0 software from the outset with Rugby being the next areas to go live and the remainder to be commissioned over the next 18 months.

As well as the ECR ‘front end’, the legacy electromechanical supervisory systems had to be replaced with modern RTUs. Much of this work has been concluded with over 300 installed and most of these are now in operation. Eastleigh will be the final area to bring these new RTUs online. The more recently electrified lines have existing RTUs which TPCMS has been designed to communicate directly, thus minimising the need for any further upgrades.

As well as controlling the electric traction elements, the opportunity has been taken to create a separate voice network using the Voice over Internet Protocol (VoIP) standard that enables controllers at all the ECRs to talk easily with electrification engineers on site at the various outstations. This also includes upgraded ‘telephony turrets’ in the ECRs which are integrated with the TPCMS system.

The deliverables

So what will be the outcome and benefits once the project is completed? This may be summarised as follows:

A common design for ECR operation and control with screen-based work stations and large Off Desk Displays (ODDs) showing the status of every sub-station and switching site for that region.

Two identical data management centres that will monitor and store all ECR activities plus a third centre at Telent headquarters used for investigations into unusual occurrences and for testing out any new requirements or changes to how the system is operated or presented.

To maintain business continuity there will be the ability to control an ECR operation from another site should that ECR become disabled for any reason. This is being tested at the Basingstoke, Three Bridges, and Manchester ROC sites.

Improved safety measures when electrical isolations are required for maintenance purposes with on-site staff initiating the isolation but with the ECR being prevented from restoring power until a mobile app procedure has been conducted with the on-site staff. This ‘Remote Securing’ feature will be trialled at Rugby and deployed everywhere once the procedures are proven. This addition will replace the existing padlock and paper filling exercise.

A ‘private’ voice network that will allow quick communication between electrification staff across the country.

Contractual arrangements and the future

The main contract is with Telent but a number of sub-contractors have been needed for elements of the project. These include:

Cisco for the computer hardware and servers.

• Mima Group (CCD Design & Ergonomics) for ergonomics.
• CNS Cyro Cyber for cyber security protection and testing, now part of Telent.
• IP Trade for the VoIP voice network.
• Morson Projects for software development.
• Vitra for supplying the workstation desks.
• NRT for supplying the transmission links and associated bandwidth.

Clearly, this project has been challenging both for the customer (Network Rail) and the supplier, which has resulted in a much longer timeframe for completion and a significant increase in cost. The nature of the system will allow new features and improvements to be deployed nationally as the electrified rail network expands and evolves.

One current addition to the control arrangements is the advent of Static Frequency Convertors (SFCs) which synchronise the phase angle between adjacent feeder stations on the AC lines and avoid the need for neutral sections. This also permits the use of lower voltage power lines from DNOs instead of costly National Grid connections. After a trial in the Doncaster area, a live section of electrified line is in use at York where the facility can be monitored for its effectiveness. This should lead to fewer feeder stations on new electrified lines which will have beneficial cost implications but will have an impact on the TPCMS project.

Ongoing maintenance will require Telent to be proactively engaged with first line faulting through its Warwick-based 24/7 Network Operations Centre (NOC) and Security Operations Centre (SOC) monitoring which includes remote monitoring, resolution of incidents, and fast and safe deployment of patches and fixes proven on the system reference model before deployment. Telent will also give second line support for the RTU installations and a third line repair and return service for component failures. The training of ECR operators and ground level engineers and technicians is being undertaken by Network Rail.

The advent of the Rail Operating Centres (ROCs) will be the longer-term objective to house the electrification control activity to have signalling, operations, and electrification management under one roof for the various areas. Rail Engineer will monitor progress over the next two years and will update the readership once the project is complete.

Thanks are expressed to Tom Royds and James Morrissey from Telent for the technical input to this article and for allowing the reference network equipment to be viewed.

Image credit: Telent