Application Report ASC Sensor Applications at Alstom
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Use under the harshest conditions Sensors from ASC ensure both safety and comfort in rail transport Alstom is one of the world’s leading manufacturers of rail vehicles. Among other things, the company test the running dynamics and bogie strength of new trains at their Salzgitter, Germany site. Capacitive acceleration sensors from ASC GmbH – a globally leading manufacturer – provide crucial measurement data during testing. At their German works, Alstom produce regional trains, trams, rapid-transit and underground trains and locomotives. Before they can be approved for personnel transport by the German Federal Railway Authority (EBA), however, the trains must pass a host of tests under realistic conditions. “We carry out running tests and other dynamic tests, among other things. This enables us to verify that a train is technically incapable of derailing,” reported Tim Michatz, deputy director of the test laboratory for Alstom Germany. “Technically” means that the train cannot come off the track or tip over without an outside influence. In addition to train safety, riding comfort is also a priority. ASC sensors impressed with their precision and high working stability The test engineers in Salzgitter test rail vehicles in accordance with the EN14363 (running dynamics) and EN13749 (bogie strength) standards. When doing so, they are reliant on the data recorded by high-precision sensors during testing. Capacitive acceleration sensors from ASC GmbH have been used for test runs since 2013. Until then, the company were using sensors from a competitor which became defective after five years in the field. The decision for ASC as the new supplier was taken not only thanks to the high precision of the sensors, but also due to their high working stability and impact resistance – very important criteria indeed. “During tests on the wheel pairs and the bogie, impacts with a force of up to 400 g occur,” said engineer Tim Michatz of the conditions experienced. Loads like this are harmless to ASC sensors, which are actually capable of withstanding impacts up to 6,000 g. DAkkS calibration an important advantage To ALSTOM, there was another aspect which played a large role as well – ASC calibrate the sensors for their customers and have been accredited by the German Accreditation Authority (DAkkS) for this purpose. “This was a good fit, as we are also accredited by the DAkkS (as per DIN EN ISO/IEC 17025) as the ALSTOM test laboratory, meaning that the sensors we use also have to fulfil these conditions,” said Michatz. It wasn’t easy at all to find a manufacturer whose products meet these specifications, though. “Many of them spare the effort and don’t have their sensors calibrated with accreditation. Sometimes, they don’t even calibrate the sensors at all. In this case, the customer has to do it themselves – a

Trains are tested on sections of open rail Alstom thus received fully calibrated sensors of type ASC 44211 (uniaxial) and ASC 55211 (triaxial) made with special plug connectors and were able to use them for measurements straight away. Contrary to what you might think, they’re only used to a small degree in Salzgitter itself. The reason for this is the applicable standards, which specify that the tests must be carried out on the public rail network. For these test runs, the company use certain sections of rail with very specific properties. “For the running dynamics tests, we traverse the...

For the measurements, the ASC sensors are mounted on the wheelsets of the trains Photo: Alstom Six to eight weeks of continuous use Although the running dynamics of Alstom trains are tested on only a few sections of track, the vehicles cover distances of around 2,000 km for bogie strength testing. “To do this, we cover a loop from the Ruhr region through Cologne to Frankfurt, stopping at every station,” said Michatz. “During the tests, we simulate normal train operation in every conceivable operating situation.” Though every test run is concerned with operating safety first and foremost,...

Still extremely stable after five years Usable data are only generated during testing if sensors are always in proper working order, however. This is why ASC offer their customers calibration as a service - including for sensors from other manufacturers. Alstom’s sensors are recalibrated every two years, and the values are recorded in an "ageing log.” Even after five years, the sensors are still extremely stable. Box Axle Bearing Monitoring Window Monitoring Driving Comfort Tests Bogie Frame Monitoring Track Monitoring Brake Tests Wheel Set Bearing Monitoring ASC's sensors measure a wide...