QuieterRail: First Measurement Campaign on Lyon’s Urban Network
As part of the QuieterRail project, a first measurement campaign focused on noise and vibration in urban rail environments was organised during summer 2025. The campaign took place on Lyon’s tramway network, which offers a diverse range of track types from ballasted to slab tracks and is operated with two types of rolling stock:
- Alstom Citadis low-floor trams,
- Stadler Tangovehicles (70% low-floor).
Rolling stock on SYTRAL’s network in Lyon: Alstom Citadis tram and Stadler Tango train.
Different situations were considered, on six measurement sites:
- For ground vibration: circulation in narrow curves and straight alignment, ground vibration generated by impact excitation (rail joints).
- For pass-by noise: noise in curves, with a particular focus on squealing noise.
Due to the urban environment constraints, most of the measurements were carried out during evening and night periods with a team of 3 to 5 engineers on 6 different sites and in a maintenance workshop.
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Test sites examples for ground vibration
(a) La Soie site, ballasted track, straight alignment, rail joint.
(b) Dauphiné site, slab track, straight alignment.
(c) Adecco site, ballasted track with under sleeper pads (USP), straight alignment. Access to a building to measure building correction factors.
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Test sites examples for noise and ground vibration in curves
(a) Tonkin test site: squeal noise measurements
(b) La Doua: curve and straight alignment for noise and vibration measurements.
Complete set of measurements was carried out for various wheel/track configurations:
- Pass-by Noise and ground vibration in curves and in straight alignment.
- Ground vibration generated by impact due to rail joints and crossings.
- Vehicle on-board instrumentation: wheel accelerometers, camera for contact point location.
- Wheel and rail roughness, wheel and rail transverse profile.
- Track characterisation for noise: track mobility, track decay rates, geometry scans of rail joints and crossings.
- Wheel characterisation: wheel mobility and wheel modal behaviour.
- Track / soil characterisation at different sites for ground vibration: line source transfer mobility and Multichannel Analysis of Surface Wave (MASW) to determine soil characteristics.
- One building characterisation (tall building): building transfer functions.
Wheel and rail transverse profile measurements
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(a) Rail roughness measurement –(b) Wheel roughness and receptance measurements
Vehicle instrumentation: (a) wheel accelerometers – (b) camera for contact point position
Data post-processing is now underway. The post-processing of measurement data is now in progress. In WP1 (Noise in curves), the test results will be mainly used for the validation of squeal noise models developed by project partners (ISVR, UPV and Vibratec).
WP 5 (Ground vibration prediction and experiments) aims to extend the computational core of the prediction method developed previously in SILVARSTAR project. These test results will allow to assess and validate model development for:
- Additional excitation mechanisms, with particular attention to trains running in curves or passing rail joints.
- Track independent vehicle indicator to classify railway vehicles in terms of ground-borne noise and vibration emission.
- Transposition of ground vibration levels at significantly different sites with different track and soil conditions.
- Building correction terms.
Acknowledgments
These measurements were carries out by Vibratec, measurement teams, with the support of SYTRAL, RATP Dev, KU Leuven, and CSTB .
Vehicle instrumentation : wheel accelerometers
Pass by noise measurement – Citadis tramway