Final Report Summary - EUREMCO (European Railway Electromagnetic Compatibility)
Executive Summary:
The EUREMCO overall objective was to promote interoperable rail traffic by harmonising and reducing the certification process of rail vehicle against Electromagnetic Compatibility (EMC). The main concept of the project was to specify the conditions for cross-accepted certification all around Europe, through sound scientific methodologies allowing for the identification of the “transfer functions” to be applied to results obtained on different test tracks in different countries, for the same supply voltage.
EUREMCO addressed the compatibility between the track circuits (installed on the railway track) and the rail vehicle. Electromagnetic Compatibility issues between both sub systems have been encountered and are mainly caused by:
• Emission of a too high interference current from the rail vehicle
• Too low immunity of the track circuits against this interference current.
The same is valid for transients, which can be considered as very short interference currents of very high intensity.
The consequences of both phenomena are unacceptable and might lead to severe accidents as long as the minimum safety level cannot be guaranteed anymore. Perturbation of the track circuits by the rail vehicle might simply render inefficient the train detection device, and recent accidents have shown what could happen if the train detection system does not work properly. The consequences are not to be calculated in k€ here, but in safety. This shows the need to have very clear emission and immunity limits for respectively the rail vehicle and the track circuits. Such limits have to be set with the corresponding assessment method, which has also to be duly validated.
Once a common understanding and limiting criteria will have been reached at a European level, it will be possible to use the results of one country also for the authorization of a vehicle in another country. Introducing a so called “transfer function” between different networks within the same power supply system will reduce the costs and time of certification since the need for additional tests, often expensive, could be removed. In a first step the objective of the EUREMCO project was to clearly identify the relevant interference current parameters of cross acceptable test lines. With the current knowledge it is expected that – through the application of the transfer function - test results could be transferred within the same power supply system.
The EUREMCO FP7 European Research project, coordinated by UNIFE – The European Rail Industry, aimed at developing a common understanding of transients and a harmonised test procedure, also addressing non electrified lines. From October 2011 to December 2014, the eighteen EUREMCO partners have cooperated in order to harmonise and reduce the certification process of rail vehicle against Electromagnetic Compatibility (EMC).
Moreover through EUREMCO it was possible to establish the following:
• Set of test signals to test track circuits against transients;
• Clear definitions and specifications for transient assessment;
• Limits for the characteristic parameters of transients for vehicles, power supply and track circuits;
• Clear understanding of influence of infrastructure on vehicles’ conducted emissions;
• Transfer function from test results within same power supply system;
• Requirement that rolling stock will not disrupt track circuits on non-electrified lines.
Project Context and Objectives:
The current authorisation process for placing rail vehicles into service, according to Technical Specifications for Interoperability (TSI) and national safety rules, is a very long and costly process. The TSIs provide common regulations for the placing in service of rail vehicles where such common understandings and harmonised rules exist. This is not the case for Electromagnetic Compatibility between rail vehicles and installed track circuits, which represent one of the major cost drivers in/of the authorisation process. Indeed each country has developed its own requirements and assessment process. In many cases these have been developed on an empirical basis and have not even been documented.
The EUREMCO objective was to harmonise and reduce the certification process of rail vehicle against Electromagnetic Compatibility (EMC). The main concept of the project was to specify the conditions for cross-accepted certification all around Europe, through sound scientific methodologies allowing for the identification of the “transfer functions” to be applied to results obtained on different test tracks in different countries, for the same power supply system. For this purpose, a common understanding of transients – very short and very high interference currents –and a harmonized test procedure was also developed. By addressing also non electrified lines, the EUREMCO project covered the whole European railway network. By closing the corresponding “open points” in the TSIs, the EUREMCO project will lead to a time and cost reduction of the certification process of rail vehicle against Electromagnetic Compatibility issues, which correspond to an estimated saving of €60m for the next 15 years.
In order to reach the aforementioned objectives, each EUREMCO Work Package had its own objectives:
WP2 - Evaluation of interference currents - Handling of transients
The main objective was to establish how transients should be handled in a commonly accepted way for interpretation of conducted interference certification data.
Currently, there are no standards/norms or procedures addressing the effects of transients on track circuits. The problem is recognized by several system operators as occurrences arise on the networks. Most operators use a variety of ways to deal with these issues and, most of the time, it is done on a case by case basis. The vehicle and track signalling systems suppliers also have extensive data with respect to transients. The sharing of these operator and manufacturer data with the European community of experts was seen as being a key part of this work package.
The objectives of WP2 were to:
• Define the typical transients occurring during interference current measurements;
• List the different types of phenomena that shall be considered in vehicles and Track circuit designs;
• Provide a good description of the transient phenomena;
• Define the criteria required to evaluate immunity to transient interference effects on the TS 50238-2 preferred track circuits;
• Generate standard method and test procedures to characterize the transients;
• Propose methods and rules for evaluating and analyse transient effects;
• Classification and characterization of the critical and non-critical transients for the track circuits selected in Task 2.1 for the different power supply systems;
• Survey of recorded problems based on historical data.
WP3 - Qualification of EMC cross accepted test tracks – 15 kV
The TS 50238-2 “Compatibility between rolling stock and train detection systems – Part 2: Compatibility with track circuits” defines, for the purpose of ensuring compatibility between rolling stock and track circuits, the limits for conducted interference from rolling stock and the measurement method for verifying conformity of rolling stock to these limits.
Main parts of this Technical Specification are known and already in practical use in single countries for different power supply systems (e.g.15 kV/16.7 Hz). But nevertheless some significant points – concerning mainly the cross acceptance of the results - are still open and have to be closed with the further development of the TS to an European standard (EN) and the definition of a frequency management for track circuits by the ERA.
WP4 - Qualification of EMC cross accepted test tracks – 25KV
The objective of this work package was to define and propose European wide cross accepted test tracks for the 25 kV / 50 Hz power supply system.
European wide cross accepted test tracks would give the possibility to perform conducted emission tests for several countries / infrastructures only once. The test results of these tests could be used for certification in all countries with 25 kV systems.
A better understanding of the influence of test tracks and infrastructure could also lead to a harmonized test philosophy. The measurements and simulations will help to fully understand the influence of vehicles with roof cables and thus simplify the design and the certification of this type of vehicles.
WP5 - Qualification of EMC cross accepted test tracks – DC
The objective of this work package was to study the influence of the infrastructure on the conducted emissions generated by railway vehicles on DC power supply systems in order to define the relevant requirements for European wide cross accepted test tracks which could allow to perform only once the measurements of harmonic currents for several countries.
Simulations and measurements had to be performed to assess the differences of harmonic currents generated by a same vehicle on several test tracks in different countries, to understand and determine the most influential parameters of networks and to check if a transfer function could be defined from test results for different infrastructure conditions.
WP6 - Test specification for rolling stock for non-electrified lines
On non-electrified lines, each single country of the EU has established rules and methods in order to handle influencing currents for track circuits. The objective of this work package was to enable for the first time a harmonization of the rolling stocks in EU in term of current interfering with track circuits on non-electrified lines.
To succeed in these objectives, the following tasks were undertaken:
• A bibliographic study on all the influencing currents created by rolling stocks on non-electrified lines and on all the existing recommendation applied on the metallic structure in EU to avoid influencing current.
• A definition of a common recommendation for rolling stocks
• A definition of a test method to verify the influencing current created by rolling stocks and validation of the recommendation.
Project Results:
High level objectives
As explained previously, the overall goal of the EUREMCO project was to promote interoperable rail traffic in Europe by:
• reducing cost and time of vehicle certification providing cross-accepted assessment methods and the associated transfer functions;
• Closing “open points” in the TSI’s related to the electromagnetic compatibility between rail vehicle and track circuits.
The TS 50238-2 defines the measurement method for the rolling stocks to respect the interference current limit of track circuits. The contents of the Technical Specification is known and used partly in some countries individually during the certification process. However these requirements do not always match with national requirements that contain some additional rules specified by the different countries and operators. A recent survey (EMC for European Railways: Study to collect and document rules, processes and procedures to verify the Electromagnetic Compatibility (EMC) of railway vehicles in Member States of the European Railway Area, Lloyd’s Register for European Railway Agency, September 2010) performed on behalf of the European Railway Agency has shown that most of them are even not written down!
Still some points are opened e.g. concerning the handling of transients, the cross acceptance of interference current measurement results and the test specification for rolling stock for non-electrified lines. It is in the focus of EUREMCO to close this open point.
Technical objectives
In order to fulfil the general objectives of EUREMCO, the following specific objectives have been addressed:
• Handling of transients
Within the normal operation, trains produce various types of transient waveforms that may interfere with track circuits at different extent. These transients are originated for example by switching on/off the main circuit breaker or other components of the power supply/traction units, or by step-like changes in applied load of main traction converters and auxiliary converters, (e.g. control of wheel slipping or skidding by protection circuits and algorithm).
Given the large set of sources and their operating conditions, transients are expected to exhibit widely variable characterizing parameters; for the time domain these parameters consist of rise time, peak value, time duration, possible superimposed ringing oscillations, while for the frequency domain the parameters are represented by the various spectral components, their behaviour versus time axis and correlations between groups of them. This complex scenario is due to the fact that a transient – from a classical signal processing perspective – needs to be described in the joint time-frequency domain and then this description must be used and synthesized for the specific analysis, with great care in preserving the information. Furthermore, transients produced by other trains running on the same track or adjacent tracks may combine: it depends on the properties of the transfer function (in this particular case, meaning transfer between two adjacent tracks) and on the propagation along the same tracks. These other transients generated by other trains could partly be influencing the same track circuit under test and influence the measurement results.
The response of a track circuit to transients may be very different depending on several factors, including non linearities, saturation effects and so on. Depending on the quality and quantity of the produced transient current and the immunity of the track circuit to transient effects, a track circuit may be influenced or may not be influenced. With respect to the evaluation and assessment of measured transient current, no precise rules and definitions currently exist.
It was the aim of the project to focus on a set of preferred track circuits and to identify by means of adequate indices the relevant critical transients influencing track circuit operation, so that unambiguous reproducible harmonized procedures may be defined for the evaluation of transients in the assessment process of a vehicle.
• Cross accepted results of tests and selection of reference test tracks
In some countries, tests procedures are completely empirical and consist in running with the rail vehicle a certain number of times on a defined track. If at each test run the installed track circuit detects the train, the rail vehicle is deemed to be compliant with the given track circuits. This kind of methodology is clearly not satisfactory, it cannot be used in the context of Technical Specifications for Interoperability and it is not even at all valid for any additional authorisation for the placing in service in any third country through cross-acceptance mechanisms.
In order to extend the certification to another country, each test performed during the certification process must be reproduced in the other country with the specific national requirements for test tracks and the test methodologies. Indeed, infrastructure conditions and parameters, operating conditions and traffic, etc. vary from country to country. Therefore, the cross acceptance of test results becomes difficult due to the specification of these country specific test requirements.
In order to address the above, the Work Program of the project was organised around the following five Work Packages:
• WP2 - Evaluation of interference currents - Handling of transients
• WP3 - Qualification of EMC cross accepted test tracks – 15 kV
• WP4 - Qualification of EMC cross accepted test tracks – 25KV
• WP5 - Qualification of EMC cross accepted test tracks – DC
• WP6 - Test specification for rolling stock for non-electrified lines
The main scientific and technologic results and foregrounds developed during the project are described in the following sections dedicated to each WP.
WP2 - Evaluation of interference currents - Handling of transients
The following tasks have been achieved in this WP:
- The characteristics of the transients that were deemed relevant for the investigation of interference issues and related modelling activities for the considered power supply systems of interest in the project were defined. The document that was produced represents an initial definition of the general characteristics of the selected transients to focus on, for the successive definition of models and for their validation. It was showed that the existing track circuits are, due to diverse measures, widely immune to transients. Furthermore the responses showed, that unavoidable transients occurring in the course of homologation tests on vehicles were identified as transients and then dropped out for the assessment of the test results.
- The transient sources have been analyzed and characterized. A source-based classification has been made, which allows the selection of transients that have a strong signature, and are expected to occur frequently in railways systems. Then, the study of the influence of various parameters has been performed, showing how the power supply, the infrastructure and the train can modify the behaviour of the transient signal from its source to the track circuit receiver. A model of the system {track circuit + transient} has been created, in order to investigate the behaviour of a widely installed track circuit receiver subject to some transient signals. These are: inrush current, pantograph bounce, and circuit breaker opening. The UM71 track circuit has been proposed by SNCF and retained in the study. It has been shown that the transient signal, in certain circumstances, can significantly degrade the receiver voltage of the track circuit system. The ratio of imbalance of the TC, as well as the position of the transient on the TC, has an efficient effect on the receiver voltages, as expected from experience.
- Tested track circuits in laboratory for susceptibility to transients.
- Tested track circuit susceptibility to transients on a test track in real operating condition.
- Defining a proposed method for transient acceptance.
WP3 - Qualification of EMC cross accepted test tracks – 15 kV
ÖBB, SBB and DB AG carried out a common measurement campaign in 2010 with the aim to validate the actual version of the TS 50238-2 for 15 kV/16.7 Hz power supply systems. For these measurements a vehicle (Taurus locomotive) was prepared with different input impedances for the simulation of roof cables and was running with the same traction unit configuration – including traction software – in the three countries. Measurement results of this measurement campaign were used for the analysis and evaluation of the influence of infrastructure parameters on the interference current behavior. Furthermore Emkamatik made a lot of simulation analyses on the interference current behavior of vehicles running on the 15 kV/16.7 Hz network.
Based on numerous analyses, evaluations of measurement and simulation data were carried out and finalized and considerations on a statistical method for a cross acceptable evaluation of measurement results were achieved: For the definition of acceptance criteria for 15 kV/16.7 Hz networks the statistical approach was developed, a set of minimum requirements for test tracks for 15kV/16.7 Hz networks was defined and the final validation measurement campaign was carried out with a locomotive Re482-2 on numerous tracks of the SBB, ÖBB and DB network in Austria, Switzerland and Germany.
WP4 - Qualification of EMC cross accepted test tracks – 25KV and WP5 - Qualification of EMC cross accepted test tracks – DC
WPs 4&5 operated in parallel although they addressed two different power supply systems. The objective of these work packages was to define and propose European-wide cross accepted test tracks for the 25kV / 50 Hz and DC power supply systems, respectively.
Validation test in Velim were performed and the results were used to check the defined criteria for test tracks and the proposed normalisation method. Test methods, requirements for test tracks and evaluation methods were refined accordingly.
WP6 - Test specification for rolling stock for non-electrified lines
The bibliographic study showed that few countries in the EU experienced issues on non-electrified lines, and defined a test method. However, regarding the theoretical possibilities of perturbing the track circuits, a recommendation that will prevent future rolling stocks from interfering with track circuits on non-electrified lines was defined. Then the test method was delivered to allow for the test campaign to be carried out.
Common test requirements – based on the existing national rules – were defined and the validation of the different test methods showing the comparability of the single tests results was achieved.
Potential Impact:
Within EUREMCO, one of the goals is to close “open points” in the TSI’s as well as where possible develop common understanding of Electromagnetic compatibility issues and cross-accepted certification procedure to be efficient regarding time and cost, which is necessary in order for the TSI’s to be successful. To ensure the implementation into the corresponding standards and in the TSI’s, a particular focus was made in each WP to ensure that the proposals for new or revised standards are of a high quality, directly applicable and are convincing of the safety, effectiveness, efficiency and feasibility of the proposed certification process. To this end there was also a structured communication with the various stakeholders like ERA, CEN/CENELEC, National Safety Authorities and other railway stakeholders involved in other European research projects within the framework of the so called Advisory Council.
The EUREMCO partners have significant involvement within standardisation bodies which will enable the objective to develop and implement TSI’s. Many partners, particularly the manufacturers and operators, are involved with experts in standardisation groups for proposal of EN norms, TSI’s and national standards. This extensive involvement of the stakeholders gives the Consortium a very good understanding of the needs of the standards as well as providing a direct route to the dissemination and acceptance of them.
Through EUREMCO, it was possible to establish the following:
• Set of test signals to test track circuits against transients;
• Clear definitions and specifications for transient assessment;
• Limits for the characteristic parameters of transients for vehicles, power supply and track circuits;
• Clear understanding of influence of infrastructure on vehicles’ conducted emissions;
• Transfer function from test results within same power supply system;
• Requirement that rolling stock will not disrupt track circuits on non-electrified lines.
In order to maximise the communication and exploitation of project outputs, the partners of the project used several effective communication systems: participation to congresses, technical fairs, publication in scientific journal, design and operation of a public area in the website.
A public website was created and maintained, and information relevant to the project was made available through this. The website was updated as the project progressed. Two leaflets were produced and distributed at the numerous events at which EUREMCO was presented.
Examples of the fora in which EUREMCO was presented include:
• UNIFE General Assembly 2012, 2013 and 2014;
• InnoTrans 2012 and 2014;
• Transport Research Arena 2014;
• Railways 2014 conference (Ajaccio, France);
• Nordic GIG - August 2014 (Oslo, Norway)
In order to ensure that project outcomes are well known and reach targeted decision makers, the project made sure that the whole railway industry and the railway operators (including also the ones not involved in the consortium) are aware of EUREMCO’s outcomes through UNIFE’s internal committees and the EUREMCO public website. Moreover the EUREMCO progress and results were presented during five Advisory Council meetings.
List of Websites:
More information is available on the project’s website: www.euremco.eu
Coordinator’s Contact detail:
Stefanos GOGOS
UNIFE - The European Rail Industry
Avenue Louise 221
B-1050 Brussels
Office: +32 2 431 04 62
stefanos.gogos@unife.org
The EUREMCO overall objective was to promote interoperable rail traffic by harmonising and reducing the certification process of rail vehicle against Electromagnetic Compatibility (EMC). The main concept of the project was to specify the conditions for cross-accepted certification all around Europe, through sound scientific methodologies allowing for the identification of the “transfer functions” to be applied to results obtained on different test tracks in different countries, for the same supply voltage.
EUREMCO addressed the compatibility between the track circuits (installed on the railway track) and the rail vehicle. Electromagnetic Compatibility issues between both sub systems have been encountered and are mainly caused by:
• Emission of a too high interference current from the rail vehicle
• Too low immunity of the track circuits against this interference current.
The same is valid for transients, which can be considered as very short interference currents of very high intensity.
The consequences of both phenomena are unacceptable and might lead to severe accidents as long as the minimum safety level cannot be guaranteed anymore. Perturbation of the track circuits by the rail vehicle might simply render inefficient the train detection device, and recent accidents have shown what could happen if the train detection system does not work properly. The consequences are not to be calculated in k€ here, but in safety. This shows the need to have very clear emission and immunity limits for respectively the rail vehicle and the track circuits. Such limits have to be set with the corresponding assessment method, which has also to be duly validated.
Once a common understanding and limiting criteria will have been reached at a European level, it will be possible to use the results of one country also for the authorization of a vehicle in another country. Introducing a so called “transfer function” between different networks within the same power supply system will reduce the costs and time of certification since the need for additional tests, often expensive, could be removed. In a first step the objective of the EUREMCO project was to clearly identify the relevant interference current parameters of cross acceptable test lines. With the current knowledge it is expected that – through the application of the transfer function - test results could be transferred within the same power supply system.
The EUREMCO FP7 European Research project, coordinated by UNIFE – The European Rail Industry, aimed at developing a common understanding of transients and a harmonised test procedure, also addressing non electrified lines. From October 2011 to December 2014, the eighteen EUREMCO partners have cooperated in order to harmonise and reduce the certification process of rail vehicle against Electromagnetic Compatibility (EMC).
Moreover through EUREMCO it was possible to establish the following:
• Set of test signals to test track circuits against transients;
• Clear definitions and specifications for transient assessment;
• Limits for the characteristic parameters of transients for vehicles, power supply and track circuits;
• Clear understanding of influence of infrastructure on vehicles’ conducted emissions;
• Transfer function from test results within same power supply system;
• Requirement that rolling stock will not disrupt track circuits on non-electrified lines.
Project Context and Objectives:
The current authorisation process for placing rail vehicles into service, according to Technical Specifications for Interoperability (TSI) and national safety rules, is a very long and costly process. The TSIs provide common regulations for the placing in service of rail vehicles where such common understandings and harmonised rules exist. This is not the case for Electromagnetic Compatibility between rail vehicles and installed track circuits, which represent one of the major cost drivers in/of the authorisation process. Indeed each country has developed its own requirements and assessment process. In many cases these have been developed on an empirical basis and have not even been documented.
The EUREMCO objective was to harmonise and reduce the certification process of rail vehicle against Electromagnetic Compatibility (EMC). The main concept of the project was to specify the conditions for cross-accepted certification all around Europe, through sound scientific methodologies allowing for the identification of the “transfer functions” to be applied to results obtained on different test tracks in different countries, for the same power supply system. For this purpose, a common understanding of transients – very short and very high interference currents –and a harmonized test procedure was also developed. By addressing also non electrified lines, the EUREMCO project covered the whole European railway network. By closing the corresponding “open points” in the TSIs, the EUREMCO project will lead to a time and cost reduction of the certification process of rail vehicle against Electromagnetic Compatibility issues, which correspond to an estimated saving of €60m for the next 15 years.
In order to reach the aforementioned objectives, each EUREMCO Work Package had its own objectives:
WP2 - Evaluation of interference currents - Handling of transients
The main objective was to establish how transients should be handled in a commonly accepted way for interpretation of conducted interference certification data.
Currently, there are no standards/norms or procedures addressing the effects of transients on track circuits. The problem is recognized by several system operators as occurrences arise on the networks. Most operators use a variety of ways to deal with these issues and, most of the time, it is done on a case by case basis. The vehicle and track signalling systems suppliers also have extensive data with respect to transients. The sharing of these operator and manufacturer data with the European community of experts was seen as being a key part of this work package.
The objectives of WP2 were to:
• Define the typical transients occurring during interference current measurements;
• List the different types of phenomena that shall be considered in vehicles and Track circuit designs;
• Provide a good description of the transient phenomena;
• Define the criteria required to evaluate immunity to transient interference effects on the TS 50238-2 preferred track circuits;
• Generate standard method and test procedures to characterize the transients;
• Propose methods and rules for evaluating and analyse transient effects;
• Classification and characterization of the critical and non-critical transients for the track circuits selected in Task 2.1 for the different power supply systems;
• Survey of recorded problems based on historical data.
WP3 - Qualification of EMC cross accepted test tracks – 15 kV
The TS 50238-2 “Compatibility between rolling stock and train detection systems – Part 2: Compatibility with track circuits” defines, for the purpose of ensuring compatibility between rolling stock and track circuits, the limits for conducted interference from rolling stock and the measurement method for verifying conformity of rolling stock to these limits.
Main parts of this Technical Specification are known and already in practical use in single countries for different power supply systems (e.g.15 kV/16.7 Hz). But nevertheless some significant points – concerning mainly the cross acceptance of the results - are still open and have to be closed with the further development of the TS to an European standard (EN) and the definition of a frequency management for track circuits by the ERA.
WP4 - Qualification of EMC cross accepted test tracks – 25KV
The objective of this work package was to define and propose European wide cross accepted test tracks for the 25 kV / 50 Hz power supply system.
European wide cross accepted test tracks would give the possibility to perform conducted emission tests for several countries / infrastructures only once. The test results of these tests could be used for certification in all countries with 25 kV systems.
A better understanding of the influence of test tracks and infrastructure could also lead to a harmonized test philosophy. The measurements and simulations will help to fully understand the influence of vehicles with roof cables and thus simplify the design and the certification of this type of vehicles.
WP5 - Qualification of EMC cross accepted test tracks – DC
The objective of this work package was to study the influence of the infrastructure on the conducted emissions generated by railway vehicles on DC power supply systems in order to define the relevant requirements for European wide cross accepted test tracks which could allow to perform only once the measurements of harmonic currents for several countries.
Simulations and measurements had to be performed to assess the differences of harmonic currents generated by a same vehicle on several test tracks in different countries, to understand and determine the most influential parameters of networks and to check if a transfer function could be defined from test results for different infrastructure conditions.
WP6 - Test specification for rolling stock for non-electrified lines
On non-electrified lines, each single country of the EU has established rules and methods in order to handle influencing currents for track circuits. The objective of this work package was to enable for the first time a harmonization of the rolling stocks in EU in term of current interfering with track circuits on non-electrified lines.
To succeed in these objectives, the following tasks were undertaken:
• A bibliographic study on all the influencing currents created by rolling stocks on non-electrified lines and on all the existing recommendation applied on the metallic structure in EU to avoid influencing current.
• A definition of a common recommendation for rolling stocks
• A definition of a test method to verify the influencing current created by rolling stocks and validation of the recommendation.
Project Results:
High level objectives
As explained previously, the overall goal of the EUREMCO project was to promote interoperable rail traffic in Europe by:
• reducing cost and time of vehicle certification providing cross-accepted assessment methods and the associated transfer functions;
• Closing “open points” in the TSI’s related to the electromagnetic compatibility between rail vehicle and track circuits.
The TS 50238-2 defines the measurement method for the rolling stocks to respect the interference current limit of track circuits. The contents of the Technical Specification is known and used partly in some countries individually during the certification process. However these requirements do not always match with national requirements that contain some additional rules specified by the different countries and operators. A recent survey (EMC for European Railways: Study to collect and document rules, processes and procedures to verify the Electromagnetic Compatibility (EMC) of railway vehicles in Member States of the European Railway Area, Lloyd’s Register for European Railway Agency, September 2010) performed on behalf of the European Railway Agency has shown that most of them are even not written down!
Still some points are opened e.g. concerning the handling of transients, the cross acceptance of interference current measurement results and the test specification for rolling stock for non-electrified lines. It is in the focus of EUREMCO to close this open point.
Technical objectives
In order to fulfil the general objectives of EUREMCO, the following specific objectives have been addressed:
• Handling of transients
Within the normal operation, trains produce various types of transient waveforms that may interfere with track circuits at different extent. These transients are originated for example by switching on/off the main circuit breaker or other components of the power supply/traction units, or by step-like changes in applied load of main traction converters and auxiliary converters, (e.g. control of wheel slipping or skidding by protection circuits and algorithm).
Given the large set of sources and their operating conditions, transients are expected to exhibit widely variable characterizing parameters; for the time domain these parameters consist of rise time, peak value, time duration, possible superimposed ringing oscillations, while for the frequency domain the parameters are represented by the various spectral components, their behaviour versus time axis and correlations between groups of them. This complex scenario is due to the fact that a transient – from a classical signal processing perspective – needs to be described in the joint time-frequency domain and then this description must be used and synthesized for the specific analysis, with great care in preserving the information. Furthermore, transients produced by other trains running on the same track or adjacent tracks may combine: it depends on the properties of the transfer function (in this particular case, meaning transfer between two adjacent tracks) and on the propagation along the same tracks. These other transients generated by other trains could partly be influencing the same track circuit under test and influence the measurement results.
The response of a track circuit to transients may be very different depending on several factors, including non linearities, saturation effects and so on. Depending on the quality and quantity of the produced transient current and the immunity of the track circuit to transient effects, a track circuit may be influenced or may not be influenced. With respect to the evaluation and assessment of measured transient current, no precise rules and definitions currently exist.
It was the aim of the project to focus on a set of preferred track circuits and to identify by means of adequate indices the relevant critical transients influencing track circuit operation, so that unambiguous reproducible harmonized procedures may be defined for the evaluation of transients in the assessment process of a vehicle.
• Cross accepted results of tests and selection of reference test tracks
In some countries, tests procedures are completely empirical and consist in running with the rail vehicle a certain number of times on a defined track. If at each test run the installed track circuit detects the train, the rail vehicle is deemed to be compliant with the given track circuits. This kind of methodology is clearly not satisfactory, it cannot be used in the context of Technical Specifications for Interoperability and it is not even at all valid for any additional authorisation for the placing in service in any third country through cross-acceptance mechanisms.
In order to extend the certification to another country, each test performed during the certification process must be reproduced in the other country with the specific national requirements for test tracks and the test methodologies. Indeed, infrastructure conditions and parameters, operating conditions and traffic, etc. vary from country to country. Therefore, the cross acceptance of test results becomes difficult due to the specification of these country specific test requirements.
In order to address the above, the Work Program of the project was organised around the following five Work Packages:
• WP2 - Evaluation of interference currents - Handling of transients
• WP3 - Qualification of EMC cross accepted test tracks – 15 kV
• WP4 - Qualification of EMC cross accepted test tracks – 25KV
• WP5 - Qualification of EMC cross accepted test tracks – DC
• WP6 - Test specification for rolling stock for non-electrified lines
The main scientific and technologic results and foregrounds developed during the project are described in the following sections dedicated to each WP.
WP2 - Evaluation of interference currents - Handling of transients
The following tasks have been achieved in this WP:
- The characteristics of the transients that were deemed relevant for the investigation of interference issues and related modelling activities for the considered power supply systems of interest in the project were defined. The document that was produced represents an initial definition of the general characteristics of the selected transients to focus on, for the successive definition of models and for their validation. It was showed that the existing track circuits are, due to diverse measures, widely immune to transients. Furthermore the responses showed, that unavoidable transients occurring in the course of homologation tests on vehicles were identified as transients and then dropped out for the assessment of the test results.
- The transient sources have been analyzed and characterized. A source-based classification has been made, which allows the selection of transients that have a strong signature, and are expected to occur frequently in railways systems. Then, the study of the influence of various parameters has been performed, showing how the power supply, the infrastructure and the train can modify the behaviour of the transient signal from its source to the track circuit receiver. A model of the system {track circuit + transient} has been created, in order to investigate the behaviour of a widely installed track circuit receiver subject to some transient signals. These are: inrush current, pantograph bounce, and circuit breaker opening. The UM71 track circuit has been proposed by SNCF and retained in the study. It has been shown that the transient signal, in certain circumstances, can significantly degrade the receiver voltage of the track circuit system. The ratio of imbalance of the TC, as well as the position of the transient on the TC, has an efficient effect on the receiver voltages, as expected from experience.
- Tested track circuits in laboratory for susceptibility to transients.
- Tested track circuit susceptibility to transients on a test track in real operating condition.
- Defining a proposed method for transient acceptance.
WP3 - Qualification of EMC cross accepted test tracks – 15 kV
ÖBB, SBB and DB AG carried out a common measurement campaign in 2010 with the aim to validate the actual version of the TS 50238-2 for 15 kV/16.7 Hz power supply systems. For these measurements a vehicle (Taurus locomotive) was prepared with different input impedances for the simulation of roof cables and was running with the same traction unit configuration – including traction software – in the three countries. Measurement results of this measurement campaign were used for the analysis and evaluation of the influence of infrastructure parameters on the interference current behavior. Furthermore Emkamatik made a lot of simulation analyses on the interference current behavior of vehicles running on the 15 kV/16.7 Hz network.
Based on numerous analyses, evaluations of measurement and simulation data were carried out and finalized and considerations on a statistical method for a cross acceptable evaluation of measurement results were achieved: For the definition of acceptance criteria for 15 kV/16.7 Hz networks the statistical approach was developed, a set of minimum requirements for test tracks for 15kV/16.7 Hz networks was defined and the final validation measurement campaign was carried out with a locomotive Re482-2 on numerous tracks of the SBB, ÖBB and DB network in Austria, Switzerland and Germany.
WP4 - Qualification of EMC cross accepted test tracks – 25KV and WP5 - Qualification of EMC cross accepted test tracks – DC
WPs 4&5 operated in parallel although they addressed two different power supply systems. The objective of these work packages was to define and propose European-wide cross accepted test tracks for the 25kV / 50 Hz and DC power supply systems, respectively.
Validation test in Velim were performed and the results were used to check the defined criteria for test tracks and the proposed normalisation method. Test methods, requirements for test tracks and evaluation methods were refined accordingly.
WP6 - Test specification for rolling stock for non-electrified lines
The bibliographic study showed that few countries in the EU experienced issues on non-electrified lines, and defined a test method. However, regarding the theoretical possibilities of perturbing the track circuits, a recommendation that will prevent future rolling stocks from interfering with track circuits on non-electrified lines was defined. Then the test method was delivered to allow for the test campaign to be carried out.
Common test requirements – based on the existing national rules – were defined and the validation of the different test methods showing the comparability of the single tests results was achieved.
Potential Impact:
Within EUREMCO, one of the goals is to close “open points” in the TSI’s as well as where possible develop common understanding of Electromagnetic compatibility issues and cross-accepted certification procedure to be efficient regarding time and cost, which is necessary in order for the TSI’s to be successful. To ensure the implementation into the corresponding standards and in the TSI’s, a particular focus was made in each WP to ensure that the proposals for new or revised standards are of a high quality, directly applicable and are convincing of the safety, effectiveness, efficiency and feasibility of the proposed certification process. To this end there was also a structured communication with the various stakeholders like ERA, CEN/CENELEC, National Safety Authorities and other railway stakeholders involved in other European research projects within the framework of the so called Advisory Council.
The EUREMCO partners have significant involvement within standardisation bodies which will enable the objective to develop and implement TSI’s. Many partners, particularly the manufacturers and operators, are involved with experts in standardisation groups for proposal of EN norms, TSI’s and national standards. This extensive involvement of the stakeholders gives the Consortium a very good understanding of the needs of the standards as well as providing a direct route to the dissemination and acceptance of them.
Through EUREMCO, it was possible to establish the following:
• Set of test signals to test track circuits against transients;
• Clear definitions and specifications for transient assessment;
• Limits for the characteristic parameters of transients for vehicles, power supply and track circuits;
• Clear understanding of influence of infrastructure on vehicles’ conducted emissions;
• Transfer function from test results within same power supply system;
• Requirement that rolling stock will not disrupt track circuits on non-electrified lines.
In order to maximise the communication and exploitation of project outputs, the partners of the project used several effective communication systems: participation to congresses, technical fairs, publication in scientific journal, design and operation of a public area in the website.
A public website was created and maintained, and information relevant to the project was made available through this. The website was updated as the project progressed. Two leaflets were produced and distributed at the numerous events at which EUREMCO was presented.
Examples of the fora in which EUREMCO was presented include:
• UNIFE General Assembly 2012, 2013 and 2014;
• InnoTrans 2012 and 2014;
• Transport Research Arena 2014;
• Railways 2014 conference (Ajaccio, France);
• Nordic GIG - August 2014 (Oslo, Norway)
In order to ensure that project outcomes are well known and reach targeted decision makers, the project made sure that the whole railway industry and the railway operators (including also the ones not involved in the consortium) are aware of EUREMCO’s outcomes through UNIFE’s internal committees and the EUREMCO public website. Moreover the EUREMCO progress and results were presented during five Advisory Council meetings.
List of Websites:
More information is available on the project’s website: www.euremco.eu
Coordinator’s Contact detail:
Stefanos GOGOS
UNIFE - The European Rail Industry
Avenue Louise 221
B-1050 Brussels
Office: +32 2 431 04 62
stefanos.gogos@unife.org