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N. Lagata, J.C.O. Nielsen, M. Maglio, T. Vernersson, "Effect of Unsupported Sleepers on Wheel Impact Load Detector Performance", in J. Pombo, (Editor), "Proceedings of the Seventh International Conference on Railway Technology: Research, Development and Maintenance ", Civil-Comp Press, Edinburgh, UK, Online volume: CCC 15, Paper 18.7, 2026, doi:10.4203/ccc.15.18.7

Keywords: dynamic vehicle–track interaction, wheel flat, wheel impact load detector, unsupported sleeper, rail seat load, rail rotation.

Abstract

Wheel-rail impact loads caused by discrete wheel tread irregularities, such as wheel flats, can lead to severe damage to both vehicles and track infrastructure. To monitor wheel out-of-roundness, peak loads are commonly measured using wheel impact load detectors. Depending on the detector type, these peak loads may, for example, be derived from post-processing of recorded rail shear forces, rail seat loads, or rail rotations. To ensure accurate load measurements, minimise operational costs, and avoid unnecessary stopping of trains, the detectors must be robust and reliable. This numerical study investigates how unsupported (voided) sleepers within the detector area influence the resulting wheel-rail contact force signature and the unprocessed (raw) sensor signals in the presence of a wheel flat. The analysis considers void depths of up to 4 mm beneath two adjacent sleepers. The effect of unsupported sleepers is analysed through numerical simulations using the in-house software DIFF, in which the dynamic vehicle–track interaction is solved in the time domain. The results show that rail rotation and rail seat load are the most affected by unsupported sleepers, as the increased local track flexibility alters the sleeper--ballast interaction and influences the load distribution along the detector.

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Front Page Browse CCC CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Conferences ISSN 2753-3239 CCC: 15 PROCEEDINGS OF THE SEVENTH INTERNATIONAL CONFERENCE ON RAILWAY TECHNOLOGY: RESEARCH, DEVELOPMENT AND MAINTENANCE Edited by: J. Pombo Paper 18.7 Effect of Unsupported Sleepers on Wheel Impact Load Detector Performance N. Lagata¹, J.C.O. Nielsen¹, M. Maglio² and T. Vernersson¹ ¹Department of Mechanical Engineering/CHARMEC, Chalmers University of Technology, Gothenburg, Sweden ², Trafikverket, Gothenburg, Sweden doi:10.4203/ccc.15.18.7 Full Bibliographic Reference for this paper N. Lagata, J.C.O. Nielsen, M. Maglio, T. Vernersson, "Effect of Unsupported Sleepers on Wheel Impact Load Detector Performance", in J. Pombo, (Editor), "Proceedings of the Seventh International Conference on Railway Technology: Research, Development and Maintenance ", Civil-Comp Press, Edinburgh, UK, Online volume: CCC 15, Paper 18.7, 2026, doi:10.4203/ccc.15.18.7 Keywords: dynamic vehicle–track interaction, wheel flat, wheel impact load detector, unsupported sleeper, rail seat load, rail rotation. Abstract Wheel-rail impact loads caused by discrete wheel tread irregularities, such as wheel flats, can lead to severe damage to both vehicles and track infrastructure. To monitor wheel out-of-roundness, peak loads are commonly measured using wheel impact load detectors. Depending on the detector type, these peak loads may, for example, be derived from post-processing of recorded rail shear forces, rail seat loads, or rail rotations. To ensure accurate load measurements, minimise operational costs, and avoid unnecessary stopping of trains, the detectors must be robust and reliable. This numerical study investigates how unsupported (voided) sleepers within the detector area influence the resulting wheel-rail contact force signature and the unprocessed (raw) sensor signals in the presence of a wheel flat. The analysis considers void depths of up to 4 mm beneath two adjacent sleepers. The effect of unsupported sleepers is analysed through numerical simulations using the in-house software DIFF, in which the dynamic vehicle–track interaction is solved in the time domain. The results show that rail rotation and rail seat load are the most affected by unsupported sleepers, as the increased local track flexibility alters the sleeper--ballast interaction and influences the load distribution along the detector. download the full-text of this paper (PDF, 8680 Kb) go to the previous paper go to the next paper return to the table of contents return to the volume description
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