NEWSLETTER

OvERviEW Of ECUC aNd iTS ObjECTivESThe EU-funded ECUC project – Eddy Current Brake Compatibility – aims to prove that Eddy Current Brake (ECB) is a highly effective and applicable solution for increasing the braking capacity of new high-speed trains. Moreover it aims to solve the concerns raised by infrastructure managers by proposing concrete and realistic solutions to overcome any possible drawbacks that ECB have experienced on some lines.

ECUC is composed of 8 partners: 2 large enterprises, 1 small-medium enterprise, 1 European association, 1 research centre, 2 railway operators and 1 infrastructure manager. These partners have gained extensive knowledge whilst working in key positions in the development of ECB during the last year. This positive starting point means that progress beyond the state of the art has been facilitated through an improved understanding of the interaction between eddy-current brake, track and trackside signalling equipment.

The linear ECB is based on a simple principle: a magnetic field across an air gap between the bogie mounted magnets and the rail head produces a braking force due to eddy-current losses (Courants de Foucault). There is no mechanical contact between the brake and track, as the magnetic field operates across the air gap between train and rail. The braking force is independent of the coefficient of friction, and these brakes ensure high efficiency regardless of wheel-rail adhesion. This means that relatively high braking forces, which remain almost constant, even in high-speed applications, can be applied. The braking force can be accurately controlled by regulating the magnetic field.

Eddy-currents are induced by movement of the train in a magnetic field, which means that eddy-current

braking cannot be used as a parking brake. Deceleration is dependent on speed, and the faster the train, the greater the braking force, which depends on the magnetic field. This allows for finely controlled braking, as the magnetic field is created using electromagnets fed from an external power supply.

The use of linear eddy-current brakes in rolling stock shortens the stopping distance and reduces the dependency of the actual braking capability on the wheel/rail adhesion properties. Therefore, rail safety is potentially increased. ECB will also contribute to improving the railway traffic flow on ETCS lines by safely increasing the guaranteed decelerations used for braking curves. Moreover, these brakes also allow the use of friction braking systems to be considerably reduced, thus reducing their Life Cycle Cost to a large extent.

ECB has been used and applied successfully (e.g., in Germany) for many years in a small percentage of vehicles. Nevertheless, some electromagnetic incompatibilities and thermo-mechanical issues between the braking system and the infrastructure have been detected. On one hand, some signalling systems such as axle counters or hot wheel detectors are disturbed by the signals radiated from ECB. On the other hand, the elevated rail head temperatures which increase longitudinal forces and introduce extra vertical force can lead to the buckling of the rail.

Therefore, the main advantages of using ECB in trains are the following ones. First of all, non-wearing, no smell and no fine-dust are emitted. Moreover, as it is independent of adhesion between wheel and rail, it leads to an improved safety, especially in the case of reduced adhesion

MAY 2015

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coefficients. In terms of cost, the ability to perform most service brake applications without using the friction brake results in a reduction of maintenance costs. In addition, if the excitation power supply is independent of the catenary supply, ECB is a reliable safety device which can be used for emergency brake applications.

Nevertheless, the use of this system incurs some drawbacks that have to be taken into account during the project. The installed ECB is heavy equipment to be mounted on the bogie, so the bogie to support this braking system needs to be specifically designed and the control of the air gap between rail and magnet is also critical. Finally and at present, infrastructure managers limit its application to slab track and specific ballasted tracks and some interference with rail mounted and lineside (signalling) equipment have been identified.

A new generation linear eddy-current brake will be designed and the study of incompatibilities will be performed in two domains: electromagnetic and thermo-mechanical. As a result, ECUC proposes also new designs and engineering and operational guidelines for eddy-current brakes and signalling equipment, and in its last stages it will define Technical Recommendations for the correct interoperable functioning of the ECB in a complex railway system and input for revisions to Technical Specifications for Interoperability.

With the aim of analysing the interaction between ECB and the rolling stock, trackside equipment and the track, the following second level objectives have been defined in ECUC project:

>> Improvement of the understanding of the interaction between the eddy-current brake and the track and trackside signalling equipment.

>> Identification of critical thermo-mechanical and electromagnetic parameters and the related vehicle and trackside compatibility limits.

>> Design of a test setup and test site that enables the approval tests for linear eddy-current brake systems focusing not only on the functionality but also on thermal, mechanical and electromagnetic requirements.

>> Design of a test procedure that recreates representative worst-case conditions to prove the compatibility between eddy-current brake, rolling stock, track and the signalling systems.

>> Development of new design, engineering and operational guidelines for eddy-current brakes and trackside signalling equipment.

>> Improvement of the standardisation process of ECB.

In order to ensure that the research and innovation objectives of ECUC project are achieved, a clearly defined work program was drawn up and divided in five technical work packages and two work packages dedicated to management and dissemination. The results of WP2 contains the definition of the design parameters and requirements of ECB based on the analysis of all the actors involved in this project (ECB, rolling stock, track, trackside equipment). Moreover, WP3 has started at the beginning of 2013 and the interaction between ECB and the track and trackside equipment is being characterised. WP4 has been now finalised with the definition of the conditions that maximize the emitted interferences created by the ECB system. WP5 is currently defining the test site, test procedure and test setup for the measurement of the ECB emissions and thermo-mechanical behaviour and to carry out the relevant laboratory and line tests. WP6, which has just started, will define, on one hand, the design, engineering and operational guidelines of the operational ECB, its installation, the tracks and the signalling systems while, on the other hand, it will provide an input for the issue of a Technical Recommendations for the ECB and the infrastructure.

ECUC Project Team

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Eddy CURRENT bRakE COmpaTibiLiTy mOdEL dESigN aNd impLEmENTaTiON

Wp3

Eddy Current Brakes (ECB) have been used in high speed trains during the last few years, particularly in Germany. They have been proven to be a reliable solution for emergency and service operation with high rates of brake forces with no material wear. The main difficulties to extend its application to other countries in Europe are based on Electromagnetic Compatibility (EMC) with wheel sensors located alongside the track and possible track buckling due to high rises in temperature. In the context of the ECUC project, computational models are provided to study worst case conditions for ECB-wheel sensor and ECB-track interaction.

Knorr-Bremse L4 and L5 linear ECBs are considered in the study. From an EMC point of view, their interaction with Frauscher RSR 123 and RSR 180 wheel sensors is considered. Three cases have been studied: the presence of the ECB passing by the wheel sensors; the analysis of the ECB switched on with low frequencies involved coming from the induction caused by a fast moving DC source; and the analysis of the ECB switched on with high frequencies emanating from the harmonics of the power supply. An EM model is realized within CST Microwave Studio environment. Proper characterisation of materials in the scenario is extracted from measurements. The temperature model is realized in FEM, modelling the typical operation over UIC 60 rail. All kinetic energy is assumed to be converted into heat and introduced to the rail. Evacuation of heat through the lateral surface is also covered in the model.

Models of the ECB are integrated with models of wheel sensors on the same CST platform for the EMC interaction. Simulations results are compared with measurements under different conditions taken in the laboratory. Input impedance of single ECB poles, radiated magnetic fields in close proximity and ECB fingerprints on wheel sensors are compared to determine the final 3D simulation

model. The final comparison shows agreement between simulated and measured results. The typical deviation is 8% for the different outcomes. It enables the study of worst case conditions. Once the model is verified, test set ups and procedures can be defined with the aid of the model. The thermal model provides temperature in the rail after the use of ECB and it can be compared to maximum temperature levels provided by technical specifications. Different scenarios are considered, varying the velocity of trains, the frequency of operation, rail initial temperature and ambient temperature.

The comparison of the available simulation with measurement results are promising and allows further steps in the project to be addressed, which includes currently ongoing measurement campaigns on track, with reasonable expectations. With this approach, once the model is corroborated after the measurement campaigns on track, worst case conditions for ECB performance when facing EMC and thermal issues can be predicted. Therefore proper test set ups can be simplified when targeting worst cases known as a priori.

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Wp4

dEfiNiTiON Of REpRESENTaTivE WORST CaSE CONdiTiONSThe main objective of this Work Package was to define the conditions which maximize the emitted interferences created by the ECB system. The conditions were not only be set on the basis of known worst situations but on a thorough understanding of all the possible situations, by means of the model of WP3. Realistic representative worst case conditions were established, and they had been the inputs for the requirements for the test site, test procedure and test setup, which were developed and executed in WP5.

1 A first task defined the worst case conditions regarding operational conditions. In this context the ECB was considered only as a brake system leaving out its emissions.

2 A second task defined the worst case conditions for signalling systems and its immunity limits for the signalling systems considering different possible operational and quality of service scenarios. Moreover, it defined the representative worst case conditions for signalling systems, not only normal operation but also transient phenomena and default conditions.

3 The third task defined worst case conditions for the rail head considering different possible operational and quality of service scenarios. It considered the effects of ECB in the infrastructure characteristics.

4 Finally, the last task defined worst case conditions for rolling stock considering different possible operational and quality of service scenarios. Constructive and operational conditions were included.

The results of this Work Package were published in the Deliverable titled “Study of worst case conditions”.

An ECB has two mechanism of influence with respect to signaling systems – magnetic fields and change of the rails magnetic properties. Only magnetic fields can be captured and validated by emission limits which are already defined in EN50238-3. Concerning the change of the rails magnetic properties caused by an ECB no emission limits exist. That means that even if magnetic fields fulfil the demands of EN50238-3 an axle counter or wheel sensor can be influenced negatively. Therefore test parameters had to be defined to capture possible worst-case conditions related to >> Speed>> Current of ECB>> Magnetic fields emitted from the ECB>> Magnetic saturation / properties of the rails>> Air gap between brake and rail

The necessary test parameter were designed by combining>> 5 different speeds – 10, 70, 120, 160, 300 km/h, with>> 6 different currents of ECB – 0, 20, 50, 75, 100%

of 95 A max. ECB current, and>> 2 air gaps – 5 and 7 mm.

Approximatively 88 test parameters were designed this way inclusive the repetition of test parameter at least two times to guarantee reproducibility. The main part was adopted from former equal test runs which were successfully performed in 2011 already during the homologation test runs Velaro D in Germany.

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TEST SiTE, TEST pROCEdURE aNd TEST SETUp dESigN aNd impLEmENTaTiON

Wp5

The general objective of this Work Package was to validate the work performed by the ECUC team in work package 3, both on test bench and through vehicle tests.

To successfully achieve these objectives, baseline measurements were completed on Knorr-Bremse’s ECB test bench (picture 1). Here it was easily possible to learn about the influences of the passive effect of different ECB generations on various typical axle counter designs. The tests were based on well established procedures. The data obtained in theses measurement campaigns was used on the one hand to verify the simulation model created by CEIT in WP3 and on the other hand to define the exact test procedures of the following vehicle tests. The focus of the bench measurements was on the so called passive effect – the interference caused by a large steel mass of the ECB passing the signalling system sensors, and on high frequency effects typically caused by power supply noise. It was understood and verified by the technical experts, that both the current ECB generation’s L5 coil (new ICE3 train) and especially the innovative new ECB concept achieved promising results (picture 2) with regard to interference with signalling system components. Both ECB coils showed an improvement – a lower degree of interference - over the L4 coil implemented in the ECB of the first generation ICE3 train.

Another task already completed was to prepare the upcoming mechanical and electrical tests of the new generation ECB. These are scheduled to be performed at the end of the Work Package.

The highlights of this Work Package, however, were clearly the track tests (pictures 3 & 4). They were performed at train speeds up to 300 kph, utilizing a first generation ICE3 train equipped with different versions of ECB, evaluating the performance of

>> The baseline ICE3 ECB’s L4 coil>> The L5 coil used in the new ICE3 trains>> The next generation ECB concept

in combination with a large variety of axle counters provided by different suppliers.

Here the focus was also on the passive effect as well as on high frequency interferences. These were previously analysed by means of CEIT’s simulation model. By means of the tests it was also possible to verify the threshold value for signalling interferences used on Knorr-Bremse’s ECB test bench (picture 1).

Many members of the ECUC project team participated in the vehicle test campaign led by the DB. The test parameters were adopted from former similar test runs (initial test runs ICE in

ECB test bench

Preparation work

Results for new generation ECB

ICE3 train passing the axle counters

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Wp6

pROjECT TEChNiCaL RECOmmENdaTiONS aNd dESigN, ENgiNEERiNg aNd OpERaTiONaL gUidELiNES

WP6 will define, on the one hand, the design, engineering and operational guidelines of the operational ECB, its installation, the tracks and the signalling systems and, on the other hand, provide an input for the issue of a Technical Recommendations for the ECB and the infrastructure (signalling systems, tracks etc.).

As this Work Package has just started, there are no relevant results to be presented at this stage. The main outcomes will be described in the next (and last) edition of the ECUC Newsletter and during the ECUC Final Conference, which will take place on 27 August 2015 in Vienna.

The first four tasks will focus on the development of design, engineering and operational guidelines for ECB, signalling systems and tracks.

In particular, Task 6.2 – Development of the design, engineering and operational guidelines for the installation of ECB in the vehicle – is dealing with the installation of eddy current brake systems in a vehicle. The deliverable D6.2 will include design and engineering guidelines.

1999/2000 and from the homologation test runs of the new ICE3 in 2011). Worst-case conditions for signaling system interference related to speed, current of the ECB, magnetic fields emitted by the ECB, magnetic saturation / properties of the rails and air gap between brake and rail – all determined in the previous Work Package – were evaluated. Overall 86 test runs were performed under the various conditions mentioned above. Overall the vehicle testing went smoothly, an important fact when considering the effort of having the train

and track infrastructure only available for a short period of time. Especially the synchronization of different data acquisition systems turned out to be very challenging. The evaluation of the enormous amounts of collected data is currently still ongoing.

Overall, all three physical signaling interference effects were successfully captured both using test bench and vehicle measurements, supporting the theoretical models established in WP3 and hence the predictability of these models.

The design requirements will describe the main installation constraints. The efforts to be supported both by the ECB itself and the supporting structure will be listed. The main functional requirements for the operation and the control of the ECB system shall also be introduced. Requirements regarding the testability and diagnostic of the full ECB system are intended to be covered.

The two last Tasks will instead develop, on one side a Project Technical Recommendation regarding ECB new requirements and the test procedure of ECB in the vehicle and, on the other side, a Project Technical Recommendations for Interoperability for the rest of the systems disturbed by ECB

Both documents will be made public after their finalization and transferred to the European Standardisation and Regulation bodies as input for future standards in the area of ECB.

New ECB in the variant of the “signaling test body” used on the running test

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paST aNd UpCOmiNg ECUC EvENTS / paRTiCipaTiON iN OThER EvENTS

2015 – UpCOmiNg EvENTS

2013, ViennaECUC presented at the Wheel Detection Forum

Eurobrake 2014, LilleECUC submitted two papers (CEIT and Knorr-Bremse)

2013, San SebastianECUC presented at XIII National ITS Congress

European User Conference 2014, BerlinECUC first results presented at CST

2013, BrusselsECUC presented during the Project Workshop

TRA2014, Paris and Innotrans2014, BerlinECUC participation

Eurobrake 2015(4-6 May 2015, Dresden)

Paper’s title: Electromagnetic and Thermal Modeling for Eddy Current Brakes in High Speed Trains and Interaciton with Wheel Sensors.Authors: D.Valderas, J.del Portillo,N.Gil-Negrete, J.I.Sancho, G.Lancaster, H.Lehmann.

ECUC final conference(27 August 2015, Vienna)

This Final conference will bring together all the project partners and will be opened to external partners such as the members of the Advisory Group, Standardisation Bodies, Infrastructure Managers, Operators, Industry, Research Centres.

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