Noise measurement of Di4

Unstad developed a measurement and analysis system for noise in the locomotive driver’s cab to verify previous measurements and establish a more accurate data basis for noise reduction. The objective was to understand how different operational conditions affect noise exposure—such as running in tunnels, use of the horn, engine load, and driving notches.

The project required the development of new software to process acoustic data and link measurement results to route data and instantaneous speed. Using a Class 2 sound level meter, a structured measurement campaign was carried out in the Di4 locomotive driver’s cab over the course of one week, with measurements taken at the driver’s head position across various driving scenarios.

The developed analysis solution made it possible to correlate noise events—such as horn activation and compressor operation—with measured sound levels, and provided detailed noise profiles from multiple runs. The delivery established a practical framework for further noise mitigation measures in train operations, with recommendations supporting the requirements of NS-EN ISO 3381:2021 and occupational health and safety regulations, and contributing to an improved driver environment, safety, and comfort.