Rail roughness measuring device

m|rail trolley
High precision measuring systems for rough operating conditions

The rolling noise of rail vehicles depends on the roughness of rails and wheels. Therefore, concerning the acoustics of rail vehicles, detailed knowledge about the unevenness of the running surface is crucial.

In particular, for acoustic acceptance tests of moving trains the different test sections have to be comparable. Accurate knowledge of the rail roughness is therefore fundamental. The measurement of rail and wheel roughness poses high precision demands on the measuring system as unevenness in the dimension of a micrometer or even less has to be reliably determined.

Müller-BBM is one of the internationally leading providers of solutions concerning the measurement of acoustic rail and wheel roughness. This is what m|rail trolley, m|rail, and m|wheel stand for: a series of robust high-precision measuring devices which are particularly suitable for outdoor use.

Typical applications are

  • Qualification of track sections for acoustic acceptance tests (according to the standards EN 15610, EN ISO 3095, TSI NOI CR/HS)
  • Estimation/simulation of rolling noise for the development of rail vehicles
  • Monitoring of the track quality in the railway network
  • Evaluation of rail grinding (according to EN 13231-3 as well as acoustic rail grinding)
  • Determination of defects which are relevant with regard to acoustics and vibrations, e.g. wheel polygons, wheel flats, rail grooves and corrugations

The calibration of these measuring systems is metrologically traceable.


m|rail trolley is a high-precision measuring system to continuously record the rail roughness. The measuring system can be operated by one person and is simply pushed along the track. In this way, even long tracks can be measured without any problem and acoustically suitable test sections can be quickly identified. Another application is the mapping of the acoustic quality of a railroad network.


  • Real-time display of the measuring signal on a Tablet PC
  • Measurement of all common grooved rails, vignole rails and track widths
  • Simple and quick measurement and evaluation according to EN 15610, EN ISO 3095 and EN 13231-3
  • Low weight
  • Power supply via USB port

Technical data

  • Measuring sensor resolution: 0.1 µm, mechanical displacement sensor
  • Scanning in longitudinal direction: 1 mm
  • Measuring velocity: max. 0.5 m/s
  • Measurement trace adjustment: continuous (manually)
  • Dimensions (length x width x height): 1255 mm x 210 mm x 210 mm
  • Length of the sliding surface: 1245 mm
  • Weight with transport bag: 21 kg

Software for measurement and data analysis

The scope of supply of m|rail trolley also includes the measuring and analysis software exactly adapted to the respective task. In this way, the device can be controlled conveniently and the measured data can be easily evaluated. The software functions at a glance:

  • Data recording and display in real time
  • Display of longitudinal velocities during the measurements
  • Data processing according to EN 15610
  • Calculation, averaging and standardized representation of roughness third-octave spectra
  • Calculation of narrowband spectra
  • Calculation of the roughness single-value indicator LλCA
  • Direct comparison with the limit curves of the relevant standards
  • Export and import of measuring data and spectra in ASCII format

Additional pages

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