Train protection systems

High-speed train visualizes the topic of derailment protection: sensors for train protection systems

Predict and prevent train derailments

Problem: Derailment caused by critical acceleration

Between the track width of railway vehicles’ axles and the gauge of the rails there usually is slackness. This is the cause for possible pendulum movement of the train right and leftwards while driving. This movement is limited by the wheel flange bouncing to the outer rail. These bounces are measurable as acceleration. If the resulting accelerations exceed a certain level, however, derailment threatens to occur.

Product solution: Derailment protection

The sensor AccTRANS is developed to measure the mentioned acceleration. It is supposed to be mounted in the outskirt area of the vehicle, directly at the bogie and it is thus sufficiently connected with its mechanical components.

If the measured acceleration lateral to the driving direction exceeds a certain critical value, the signal is used to initiate brake application or to apply a temporary speed limit. This helps to successfully avoid accidents like derailment.


Analog acceleration sensor to measure oscillation and vibration on train bogies

  • Filter configuration on request
  • Extremely rugged stainless steel housing
  • Easy integration into onboard power supply of the train
Analog acceleration sensor to measure oscillation and vibration on train bogies, EN50155 compliant

General chracteristics

AccTRANS is a single axis accelerometer based upon MEMS technology (micro-electromechanical system) capturing dynamic acceleration. A spring-mass-system continuously measures the displacement of a seismic mass. This value is proportional to the acceleration and subsequently output with a 4 - 20 mA current signal.

  • Measurement range
    ± 4 g*
  • Sensitivity
    2.0 mA/g*
  • Frequency range
    0,5 - 15 Hz*
  • Protection class
  • Temperature range
    -40 °C … +70 °C
  • Housing material
    stainless steel


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Red train symbolizes the topic of rail vehicle sensors