THE SITUATION BEFORE
From simulation to measurement
Calculations and simulations are an essential part of rail vehicle development. However, to fully understand how a component is loaded, it is sometimes necessary to measure what actually happens in operation.
CAF wanted to gain a better understanding of the loads acting on the anti-roll bar mounting points during normal service. By complementing existing analyses with real-world measurement data, the goal was to gain a clearer picture of how the component is loaded along a specific route.
Access to real-world operating data is important for understanding how components behave in service and for comparing actual performance with theoretical calculations made during the design process.
The project became a focused analysis initiative aimed at studying loads under actual operating conditions.
THE SOLUTION
Capturing what happens in the moment
To support the project, Strainlabs installed eight instrumented bolts in the anti-roll bar mounting points on a CAF vehicle operated by Euskotren.
The objective was to capture momentary changes in preload as the vehicle travelled through different sections of track. To record these variations, measurements were performed at 20 Hz, meaning the bolts collected data 20 times per second.
This high sampling frequency made it possible to capture short-term load variations that can otherwise be difficult to identify. During the approximately two-hour test run, covering around 100 kilometres, each bolt generated roughly 144,000 measurement points.
By combining load data with GPS positioning, the measurement results could be linked to different sections of the route, providing a detailed picture of how loads varied throughout the journey.
The project was carried out successfully thanks to the strong collaboration between the Strainlabs teams in Spain and Sweden. We particularly appreciated the improvements in data collection frequency and battery lifetime, which supported the testing process.
RESULTS
Insights from real operating conditions
The measurements showed that most mounting points maintained stable load levels throughout the test.
Some local load variations were observed and could be related to specific track sections and changes in track geometry. During the measurement period, no loss of preload or abnormal loading conditions were detected.
The project provided CAF with detailed operational data and additional insight into how the anti-roll bar mounting points are loaded during service.
When measurement data complements engineering analysis
Calculations and simulations will continue to play a central role in rail vehicle development. At the same time, measurements from real operating conditions can provide additional perspectives and contribute to a deeper understanding of component behaviour in practice.
By measuring directly in the bolted joints, CAF gained access to data from the exact point where loads occur. The project demonstrates how high-frequency measurements can be used as a complement to other engineering analysis when the objective is to understand real-world loading conditions.
For Strainlabs, the project also demonstrates the flexibility of the technology. The same system used for long-term monitoring can be adapted for focused analysis projects where high-resolution data is needed to capture rapid changes during operation.