Intelligent Condition Monitoring: Acoustic sensors bring new transparency to wheel set maintenance

9 September 2026 |

Wheelset bearings are among the safety-critical components of a train. Their condition affects not only operational safety but also maintenance costs and vehicle availability. In the field of wheel set monitoring, voestalpine Railway Systems has therefore developed zentrak ACOUSTIC MONITORING SENSOR. This highly sensitive measurement system evaluates acoustic signals to precisely analyze the condition of rotating bearing components during operation and to detect damage at an early stage.

Early warning system for critical components

Acoustic signals from passing trains are captured using microphones positioned along the track. Intelligent analysis of this data makes it possible to identify even the slightest changes in bearing condition – long before they lead to failure.

The dual configuration of the microphones in series ensures that the measurement of multiple bearing revolutions – even in poor weather conditions – is particularly reliable. Detection of a deteriorating bearing condition occurs at an early stage without any direct operational impact, such as a reduction in train speed, allowing maintenance planning to be carried out well in advance.

Precise analysis through acoustic measurement

zentrak ACOUSTIC MONITORING SENSOR reliably distinguishes between essential wheelset bearing noises and ambient noise. When combined with zentrak AUTOMATIC VEHICLE IDENTIFICATION, measurements are assigned to the corresponding vehicles and broken down into individual bearing components such as the inner ring, outer ring, or rolling elements.

For each vehicle, bearing damage is tracked, classified according to customer-specific thresholds, and trends are identified based on recorded data.

This results in seamless monitoring of every single bearing throughout its entire lifecycle.

More efficient maintenance through data-driven decisions

With zentrak ACOUSTING MONITORING SENSOR, maintenance measures can be planned in a more targeted and need-based manner. Instead of rigid maintenance intervals, continuous data collection enables condition-based maintenance. Customizable thresholds ensure that alarms are automatically triggered in the event of critical developments. At the same time, trend analyses provide valuable insights for optimizing maintenance strategies for wheel sets.

Early detection of bearing damages
Long-term monitoring with trend tracking of components.
Optimization of maintenance intervals for wheel set bearings.

Additional product benefits:

No moving parts for increased robustness and reduced maintenance requirements.
High reliability and availability due to measurement of multiple bearing rotations — even under poor weather conditions.
Easy removal and reinstallation in any standard sleeper.

By detecting bearing damage early on, zentrak ACOUSTIC MONITORING SENSOR plays a key role in enhancing operational safety and protecting assets within the rail infrastructure and rolling stock. At the same time, it reduces unplanned downtime and contributes to an optimized maintenance strategy.