Martin Novak


Prosoft Süd Consulting GmbH

Wheel sensors used in Train detector Systems


  • Train detector systems are used to identify trains and wagons at specific locations within a railway network
  • Information based on wheel sensor signals are used to accurately allocate information delivered by RFID (identification of wagons) and/or WTMS equipment
  • Benefits of using a wheel sensor within train detector systems output, examples and experiences


Train detector systems are used to identify trains and wagons at specific locations within a railway network, often at the location of so called wayside train monitoring systems (WTMS) – e.g. hotbox detectors, wheel set condition monitoring and noise emission measurements or similar – or at the gates of ports and terminals to record the sequence of wagons and their licence number in a freight train. They consist of a wheel sensor interface, a RFID detector module, a low power microprocessor and communication interfaces. Eventually also further sensors are added.

The WTMS and/or RFID information must be accurately allocated to a specific wagon and/or its component(s) (a bogie, wheel or axle). The allocation is based on the timestamp sequence of detected axles giving the “axle scheme” of a train (axle by time). As speed and distances are calculated from the wheel sensor signal, the accuracy of that timing is critical. An adaptive algorithm identifies each single wagon of the train based on axle distances. The variation of the distances must be less than 5 cm based on a measured axle distance of 3 m (2 axle bogie) at a speed range from 5 km/h up to 230 km/h or more. The RFID reading module of a train detector reads the wagon number stored in the RFID transponder at the moment of passage. This information is used to pinpoint the wagon of the train and also to identify the running orientation of the wagon. This enables the proper allocation of the axle oriented WTMS-measurements axle to the wagon and/or its axle or wheel.

The result is an XML-formatted “train report” available immediately after the passage of the train. This report is transmitted to a central host for further processing (collection of specific measurements, analysing for proactive maintenance support, sending an approaching alert to a port etc.)

The presentation will illustrate, how the wheel sensor was integrated in a low power embedded system together with an RFID reading module, tell about the challenges of the hardware and software interfaces and the dependency of the accuracy of the wheel sensor signals, and give an overview about the data format of the results.


Martin Novak studied at Vienna University of Technology, where he obtained his Graduate Engineer degree. Currently he works as founder and managing director at Prosoft Süd Consulting GmbH and he is also co-founder and managing director of Rail Data Services GmbH & Co. KG. His special focus lies on railway IT equipment for seamless integration of transport assets into the cross-border transport process of railway operations. Also, he focuses on the design and development of information interfaces between the different actors. Furthermore, Martin Novak is a senior developer of RFID train detector systems, railway noise monitoring equipment, DGNSS-surveying and rolling stock localization equipment.

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