64 August 2015 | Railway Gazette International IN FOCUS Braking Studying the compatibility of eddy-current

• an energised ECB with high fre- This month sees the conclusion of quencies (kHz) emanating from the the ECUC project to investigate harmonics of the power supply. the use of eddy-current brakes. Comparing the modelling results with data obtained through a measure- ment campaign, the worst interference conditions can be anticipated. Using finite element modelling, the thermal model considers the tempera- ture in the rail after the use of ECB, and compares this to the maximum tempera- ture levels permitted in the various tech- nical specifications. All kinetic energy is assumed to be converted into heat and introduced to the rail. Different scenar- ios were considered, varying the velocity of the trains, the frequency of operation, the initial rail temperature and the am- bient temperature. The thermal calcula- tions were undertaken for UIC60 profile DANIEL VALDERAS gap between bogie-mounted Practical tests in rails. Using experimental results, various Project Co-ordinator, CEIT Germany were and the rail head produces a braking used to verify the parameters were added to reflect the [email protected] force. As there is no mechanical contact EMC modelling evacuation of heat through convection or between the and track, there is no and demonstrate radiation from the lateral surface. ANDREA DEMADONNA the compatibility wear, smell or dust emissions. The use of eddy-current Technical Affairs Manager, Unife of linear ECBs can help to shorten the brakes with Developing guidelines [email protected] lineside signalling stopping distance of trains, while reduc- equipment. Based on this modelling work, the pro- ing the dependency of the braking capa- ject team was able to develop a test set-up ddy-current brakes have bility on wheel/rail adhesion. Using ECB and testing procedure that could be used proved to be a highly effective brakes for regular service braking can in the definition of approval tests for lin- way of increasing the braking considerably reduce the need to rely on ear ECBs. This test procedure would seek capacity of high speed trains, braking, extending brake block or to recreate the worst-case conditions for but to date they have not been widely pad life, saving maintenance and reduc- compatibility with axle counters. adoptedE in Europe, mainly because of ing life-cycle cost to a significant extent. With the modelling and test pro- concerns over electromagnetic compat- ECBs have been used successfully in cedures in place, ECUC moved on to ibility and thermal effects on the track Germany for many years, notably on develop new design, engineering and (RG 5.08 p301). high speed trainsets. The main hurdle to operational guidelines for ECBs and Co-funded by the European Com- extending their use to other countries are lineside signalling equipment to provide mission under FP7 Transport (contract concerns over electromagnetic compat- technical support and a proper input to 314244), the ECUC collaborative re- ibility with wheel sensors located along future standardisation. search project on Brake the track and the risk of buckling due to All of the project results and recom- Compatibility has brought together increased rail head temperatures which mendations will be presented at the eight European partners to investigate increase longitudinal forces and intro- Finite element ECUC final conference taking place in these concerns and look at ways of al- duce vertical forces. modelling was used to investigate the Wien on August 27. Further details of leviating them. The project has been The ECUC project therefore used impact of thermal the event and a registration form can co-ordinated by CEIT in Spain, work- computer modelling to study the worst stresses at the be found on the project website. n ing with Unife, Knorr-Bremse, Al- case conditions for wheel sensor and wheel-rail interface. www.ecuc-project.eu stom, SNCF, DB, Network Rail and track interaction, using Knorr-Bremse´s Frauscher Sensortechnik. L4 and L5 linear ECBs as the base case. Over the past three years, ECUC The EMC model was built using CST has developed new electromagnetic Microwave Studio. The tests looked at and thermal models for eddy-current the interaction with Frauscher’s RSR 123 brakes, new brake designs and test pro- and RSR 180 axle counters in three cases: cedures, and recommendations for the • an ECB passing the signalling device, correct interoperable functioning of where the presence of a metallic mass ECBs in a complex railway system. can be interpreted by the axle counter as a ‘wheel’; Simple principles • an energised ECB with low frequen- The linear ECB is based on a simple cies (Hz) coming from the induction principle: a across an air caused by a fast moving DC source;

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