Noise measurement inside rail vehicles according to ISO 3381

The standard specifies detailed measurement procedures for carrying out interior measurements, whereby various microphones are placed at different positions in the vehicle interior to collect representative data. Typical measurement locations include seats and aisles. The measurements must be carried out under typical operating conditions at different speeds and operating modes (e.g. acceleration, constant speed, braking).

The sound pressure levels and the third-octave spectra are measured in decibels (dB) from the raw signals. The imc WAVE software helps to record the raw data, analyze and evaluate it online and generate a report directly after the measurement.

Area of application

ISO 3381 applies to all types of rail vehicles, including: high-speed trains, passenger trains, freight trains, streetcars and metros

Operating states

• Starting noise: Noise emissions when starting the vehicle.
• Driving noise: Noise emissions while driving at constant speed.
• Braking noise: Noise emissions when the vehicle brakes.
• Stationary noise: Noise emissions when stationary, e.g. from air conditioning systems or fans.

The results of the measurements are used to evaluate the acoustic conditions in the interior and compare them with defined comfort criteria.

This may include:

• Maximum L(AFmax) and averaged sound pressure level L(Aeq)
• Frequency analyses: To identify and evaluate specific noise sources
• Evaluation of vibrations

With imc WAVE, you can create a uniform and standardized method for measuring and evaluating interior noise in rail vehicles. By complying with ISO 3381, manufacturers can ensure that their vehicles meet comfort requirements and operators can monitor and control noise exposure to ensure passenger comfort.