Invensys Rail Introduces Innovative Modular Signalling Solution
16 Nov 2011
In February 2011, Invensys Rail was awarded a contract by Network Rail to complete the resignalling of the Shrewsbury to Crewe line using the company’s Modular Signalling systems and solutions.
The contract award followed the successful completion of the development phase of Invensys Rail’s Modular Signalling programme, which included a series of demonstrations of the complete working solution to Network Rail staff at its UK headquarters, as well as the successful completion of site trials on a pilot line.
The scope of the contract incorporated all detailed design work as well as testing, installation and commissioning. The resignalling programme covers 30 miles of bi-directional signalling, seven level crossings (five of which will be new MCB-ODs) and two complex fringes and will see the installation of lightweight signals, object controllers, plug coupled cables, axle counters and the Westrace Mk 2 interlocking.
Installation work began on site at the start of March 2011, with the train detection equipment going on trial at the start of July. The system is planned to be signed into service after extensive testing in mid-2012, when control of the line will be undertaken from the Network Rail Signalling Control Centre in Cardiff; the communications network is being provided via Network Rail's Fixed Telecoms Network.
The Modular Signalling Concept
Although the Modular Signalling concept was originally developed for secondary lines, it is increasingly being recognised to have a much broader scope, offering a series of benefits to both main line and low density schemes. Providing a significantly reduced total cost of ownership, Modular Signalling not only gives rail operators the opportunity to cost-effectively replace aging signalling assets, but it also supports the economic case for much needed investment in secondary lines (that might otherwise be at risk from mounting operating costs).
A number of factors drove the development of the Modular Signalling concept, not least the need for control systems on the operational railways to be available 24 hours a day, 7 days a week and for those systems to be commissioned and maintained in the minimum amount of time and with minimum disruption.
Richard Inglis, Senior Project Manager at Invensys Rail explains these key factors: “The drivers behind this programme can be distilled down into three main factors: the cost of signalling; changing technology and changing attitudes. Clearly there has been an imperative to reduce the cost of operation, equipment, projects and ownership. However, at the same time we have seen significant improvements in network communications, the development of ETCS and equally important, a willingness across operators, suppliers and contractors to embrace new concepts. As a result we not only have the right technical environment, but the right cultural one too to bring forward innovative solutions.”
The Solution
As a result of this shift change in approach and technology, Invensys Rail developed the solution by looking across both the rail sector and other industries to bring together a suite of complementary systems and technologies.
Placing the company’s WESTRACE interlocking technology at the centre of the solution, the approach allows signalling schemes to be implemented from just a small range of core components, providing railway operators with the means of achieving cost-effective performance whilst reducing both capital and operational costs.
Richard Inglis explained the company’s system: “Our approach is based on a series of core principles, but primarily on simplicity of design and the ease and repeatability of installation processes. Essentially we not only looked at products but also examined every element of a signalling scheme to see where we could introduce different products and new processes to make both operational and cost improvements.
“As a result, we have a solution which features a small range of core components, together with standard signalling systems and a set of standard data templates. Essentially, we have developed a solution which is more typical of an off-site manufacturing process rather than a traditional signalling scheme”.
The core components of the range include:
Interlocking and Level Crossing Controllers – housed in trackside ‘bungalows’
Object Controllers – that facilitate communication between the trackside objects and the interlocking, either over a dedicated optical fibre link, or a conventional Wide Area Network
Trackside Objects – such as train detection, signals or points. All of the trackside objects are low power devices which require minimal maintenance (the design stage aims to eliminate the need for substantial support or foundations)
Cables – faster on-site termination and testing processes are possible through the use of plug coupled connections
Range of alternative power supplies – capable of operating with low voltage DC supply, to allow existing local power supplies to be re-used, whilst also enabling the use of renewable energy sources
Invensys Rail’s approach uses application data which is configured using a selection of pre-agreed constructs (selected from a library of standard ‘templates’). Using these automated processes, rather than developing bespoke data for each new project, templates then only need to be populated with specific geographical data, allowing interlocking and level crossing configuration to be achieved and verified quickly, efficiently and with minimal human intervention.
The system is also fully compatible with the requirements of ETCS, ensuring that it delivers cost-effective performance that is also future proof.
Within the system architecture, vital communications use the WESTRACE Network Communication (WNC) protocol – a SIL4, IP-based protocol which allows transmission over any Ethernet enabled communications system or dedicated cabling. Non-vital communications are also IP based. As these protocols are already widely available, the system architecture is therefore open to integrate with, or accommodate other third party equipment.
By standardising key elements of the process and taking off-site others which would normally be carried out on-site, the number of engineering hours and possession time required are both significantly reduced, impacting greatly on the overall scheme costs. Central to this are the Verification and Validation (V&V) processes, the majority of which are carried out in the company’s purpose designed hangar facility at its UK headquarters.
Verification and Validation (V&V)
V&V marks one of the core tenets of the Modular Signalling philosophy, representing a fundamental shift in the order in which processes are undertaken.
Essentially, the traditional approach would see the process as Design > Install > V&V > Commission. However, with Modular Signalling the V&V stage takes place off-site, pre-installation (Design > V&V > Install > Commission).
V&V now all takes place in a purpose-built facility at Invensys Rail’s UK headquarters, ensuring that all the equipment required for each scheme is assembled and configured off-site, allowing full system integration verification and validation to be achieved in a controlled environment prior to installation. Once through this process, the complete signalling system is then packaged for delivery to site, significantly reducing the time required on site for the installation phase and final pre-commissioning checks.
The Installation Process
Installation then is a safe, fast and straightforward process with each member of the team having the right tools, clearly defined roles and tasks (the principles being similar to that of a highly skilled, highly trained Formula 1 pit crew). The Invensys Inteletrac and Avantis process management tools are also used to help manage the logistics of moving the complete system to support the installation and commissioning phases.
Essentially, installation and commissioning activity can be achieved in just three site visits:
Visit 1 – site survey and construction mark up
Visit 2 – installation of signalling equipment
Visit 3 – power up and commissioning
Because V&V is completed off-site, and plug-coupled connections are used, commissioning activity is now reduced solely to confirming that trackside objects are correctly operated by the interlocking. Once commissioned, a fully featured diagnostic system is available, with remote access enabling engineers to do everything remotely that could also be done locally.
In summary, Richard Inglis said: “Modular Signalling delivers both efficiency benefits and cost savings across a wide range of key process areas, resulting in an installation period of just three hours per signal area, rather than several weeks.
“We firmly believe that Modular Signalling provides a fantastic opportunity for the world-wide rail industry, offering a completely new signalling solution which uses the most up to date products and technologies. The whole approach provides an attractive business case for rail operators, significantly increasing their flexibility and supporting the drive towards a 24/7, future proof railway.”