Axle counter

from Wikipedia, the free encyclopedia
Siemens axle counting rail contact when installed
Axle counting rail contact Zp30 from Thales when installed
Symbol of an axle counter in safety-related plans.

Axle counters are electronic components used to count the wheel sets of passing trains . Its principle is based on the fact that the axes counted by the connected sensors (counting point, wheel sensor) are compared when entering a track section with those when exiting.

The symbol for an axle counter usually used in signaling planning documents shows two points, crossed by a horizontal line.

While some European infrastructure operators often rely on axle counters, others only use them in exceptional cases.

technology

Several point sensors, so-called axle counting contacts or wheel sensors , are installed on a track section , which report the vehicle axles to motor-driven or electronic axle counters . Direction recognition is important for the function, which is why two contact systems are installed next to each other in axle counting contacts. Depending on the manufacturer, this is also possible in a common housing. In the case of electronic axle counters, part of the connection is installed in a track connection housing near the rail contacts, but the evaluation is usually carried out centrally in the signal box .

When entering the equipped with an axle counter section of track, the axes of the rail vehicles to be incorporated counts , during the extension counted . A previously free track section is reported as free again if the same number of counted axles has also been counted; if the number of axes counted in and counted out is not the same, the section continues to be registered as "occupied". If more axes are counted out than before, even in the meantime, then these minus axes lead to a fault and occupancy message.

At Deutsche Bahn , inductive rail contacts are mainly used: A transmitter on the outside of the rail emits a magnetic field that acts on a receiver on the inside of the rail. When a wheel moves through this field, the change in field is recognized as a "counted axis". The direction of travel is recognized by shifting the change in field direction to the second transmitter / receiver pair. The commonly used, historically developed designation as "axle counter" is therefore technically incorrect, since a wheel and not an axle is detected here.

An advantage over the track vacancy detection by track circuits is that there is no need for complex electrical insulation of the track, the length of an axle counting section only depends on the type of data transmission between the counting point and the evaluation device and is therefore practically unlimited. Also, no insulating joints interfere with the gapless track , and no special measures are required for the drive current return in electrical traction with catenary .

The disadvantage, however, is that the track is only reported indirectly and z. B. after work or disruptions, the vacancy of the relevant section must be manually determined. The basic setting of an axle counting section (section free) must then be established by an auxiliary operation that is subject to counting and verification, the axle counting basic setting .

Manufacturer

literature

  • Andreas Hegger, Ulrich-Markus Fährmann, Klaus Restetzki: Basic knowledge of the railway . Verlag Europa-Lehrmittel, 6th edition 2012, ISBN 978-3-8085-7423-2 , page 277 f.
  • Jörn Pachl: System technology for rail transport . Springer Vieweg Wiesbaden, 7th edition 2013, ISBN 978-3-8348-2586-5 , page 63 ff.

Web links

Commons : Axle Counters  - Collection of images, videos and audio files

Information about axle counters from the manufacturers:

Individual evidence

  1. ^ Andreas Hegger et al.: Basic knowledge of the railway . Verlag Europa-Lehrmittel, 6th edition 2012, ISBN 978-3-8085-7423-2 , page 277 f.
  2. ^ Andreas Hegger et al.: Basic knowledge of the railway . Verlag Europa-Lehrmittel, 6th edition 2012, ISBN 978-3-8085-7423-2 , page 275.
  3. ^ Colin Bailey: European Railway Signaling . Ed .: Institution of Railway Signal Engineers. A & C Black, London 1995, ISBN 0-7136-4167-3 , pp. 136 .
  4. ^ Andreas Hegger et al.: Basic knowledge of the railway . Verlag Europa-Lehrmittel, 6th edition 2012, ISBN 978-3-8085-7423-2 , page 492