01.01.12
Avoiding interface
Source: Rail Technology Magazine Dec/Jan 2012
Electrical engineer Dr Iñigo Adín, a researcher at CEIT (the Centre of Studies and Technical Research of Gipuzkoa, Spain), discusses the European TREND project on rolling stock electromagnetic compatibility.
Currently, rolling stock electromagnetic emissions are a major concern for train manufacturers and railway infrastructure operators.1 The available harmonised EMC standards (EN50121-2, EN50121-3-1 and EN50121-3-2) do not completely address interoperability issues caused by rolling stock interferences with signalling systems.
Moreover, these standards do not cover representative worst-case conditions derived by transients in rolling stock behaviour typically generated by feeding and track circuits’ discontinuities.
On the one hand, this situation wastes time and resources for train manufacturers when integrating rolling stock and signalling systems. Moreover, in trains that have already been tested, problems may still occasionally arise. Therefore, neither the responsibilities nor the technical solutions are straightforward.
The duration of the field testing employed to solve these kinds of problems and to go through the certification process may vary between three and 12 months, while the cost of the complete process may be anything from €25,000 to €1.5m.2
On the other hand, railway infrastructure operators suffer railway infrastructure availability reductions caused by rolling stock electromagnetic incompatibility with safety critical signalling systems. These problems might cause an estimated reduction of 10% of the availability on the most crowded lines.
The conclusions derived from the analysis carried out prior to this project are summarised in the following points:
• The certification process varies enormously in time and cost across Europe and extra requirements are in place in some countries.
• Demonstration of permanent electromagnetic compatibility of rolling stock in all possible conditions is not feasible with the current available standards.
• The RAILCOM project has made important research in the fields of EM emissions of rolling stock that affect GSM-R, track circuits and BTMs. However this is only a starting point because only some issues of the overall problem have been partially addressed.
• The research community has made significant improvements in understanding the physical phenomena that lie behind EM incompatibilities between rolling stock and other systems (track circuit, signalling and telecommunications services). Unfortunately, the research areas have been isolated and a cross-domain approach has not yet been employed.
The TREND (Test of Rolling Stock Electromagnetic Compatibility for cross-Domain Interoperability) project will address this situation by means of the design of a test setup that enables the harmonisation of freight and passenger rolling stock approval tests for electromagnetic compatibility, focusing not only on interference with broadcasting services but also on railway signalling systems.
TREND will also identify and design the cross acceptance test sites on electrified and non-electrified lines that reproduce representative worst case conditions for steady state and transient behaviours. These worst case conditions will be obtained thanks to the modelisation of rolling stock and the rail and feeding infrastructure.
The thorough analysis comprises measurement, modelisation and safety and availability analysis of the effect of rolling stock electromagnetic interferences (EMI) on the neighbouring systems. The systems potentially affected by EMI will be completely covered. This complete physical environment will permit a precise analysis of the EMI coupling model affecting the whole communication system.
Thanks to the safety and availability model of the communication systems, TREND will design a test procedure recreating representative worst-cases for rolling stock electromagnetic emissions that could affect interoperability, including transient phenomena.
TREND’s contract number is 285259, granted in the call SST.2011-2.5-1 - Rail system interoperability (regulatory and non-legislative interoperability based on technical innovations). The consortium is formed by seven expert organisations:
• Rolling Stock – CAF and CEDEX (Spain)
• Feeding and rail infrastructure – Trafikverket (Sweden)
• Broadcasting Services (which include TV, radio, Freight RFID, WFI and GSM) – York EMC Services (UK)
• Track Circuits – Lulea University of Technology (Sweden)
• GSM-R – IFSTTAR (France)
• Spot signalling systems – CEIT and CEDEX (Spain)
This project, coordinated by CEIT, will provide the technical background and evidence to define a common set of standards and procedures to deal with electromagnetic compatibility between rolling stock and its environment.
This information will enable the European authorities and standardisation bodies to establish a set of new harmonised standards and to revise and complete the current ones. This will cut the cost of interoperability demonstrations and increase companies’ competitiveness, and improve safety.
TREND’s outcomes are specially focused on the main stakeholders in the European railway industry. It is expected to reach the level of previous successful projects such as EIRE, which set the technical specifications for the interoperability of the ERTMS/ ETCS.
To ensure the involvement of the railway industry, to keep the objectives in line with the practical aims of the expected impact set by the commission, and to achieve a wider dissemination of the results obtained during the TREND project, an advisory board has been set up, comprising top-level organisations with a direct interest in the project.
The consortium will provide technical information to the advisory board members and in return, they will make suggestions and comments and disseminate the information inside and outside their organisations. The advisory board members are independent of the consortium, guaranteeing the independence of their opinions on the quality of the research. They are: European Railway Agency, the RSSB, Network Rail, BAE Systems, IMA (Applied Magnetism Institute of Spain) and GCEM (Polytechnic University of Cataluña).
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