Railway infrastructure is subject to continuous degradation due to a combination of environmental stressors, aging materials, and increasing operational loads. Among the various factors influencing track deterioration, rail surface irregularities, particularly short-wave defects, play a critical role in accelerating damage to track components. These irregularities generate dynamic and impact loads that disrupt the smooth interaction between wheels and rails, leading to rapid wear of ballast, sleepers, and other structural elements. A new paper, “Rail Surface Irregularities as a Main Driver of Rapid Track Deterioration and Their Appropriate Handling,” investigates the nature and effects of short-wave irregularities, focusing on wavelengths between 10 and 1,000 mm, and provides a methodology for detecting, quantifying, and mitigating their impact across a railway network.
Welded joints were the focus of researchers Markus Loidolt and Stefan Marschnig, as these joints are the most frequent source of such irregularities in the Austrian network. Their network-wide approach to detection and quantification enables asset management beyond localized studies to system-wide decision-making. Learn more about short-wave irregularities and how engineers can prioritize targeted maintenance strategies that reduce life cycle costs, enhance operational safety, and extend infrastructure lifespan in their paper for the Journal of Transportation Engineering, Part A: Systems at https://ascelibrary.org/doi/10.1061/JTEPBS.TEENG-8973. The abstract is below.
Abstract
Addressing the main factors contributing to rapid track deterioration is essential to minimize overall maintenance costs and improve track availability. This study focused on rail surface irregularities as a key factor in track deterioration. Since 2005, it has been possible to identify and quantify irregularities in the rail surface using rail surface measurement data collected by regular track recording cars. The analytical model presented in this paper calculates dynamic 𝑃2 forces as a function of rail surface irregularities, specific track configurations, and vehicle characteristics. A statistical correlation between 𝑃2 forces and longitudinal-level degradation, based on data from over 2,000 welds over approximately two decades, provides empirical evidence of the negative impact of rail surface irregularities on track degradation. However, this correlation is not uniform across all force levels. The track shows some ability to withstand 𝑃2 forces up to a threshold, beyond which the rate of deterioration increases significantly. The statistical analysis identifies a critical ballast pressure level of 25 N/cm2 (equivalent to a 𝑃2 force of 132.5 kN for concrete sleepers), above which track degradation accelerates. This threshold corresponds to acceptable irregularity amplitudes of 0.08 to 0.13 mm for locomotives traveling at 100 km/h and 0.12 to 0.17 mm for trains traveling at 230 km/h. Further analysis highlights the significant influence of specific track features on this degradation process. The effect is visible for all track radii. Poor ballast quality exacerbates the negative effect. Elastic sleeper pads reduce it. Potential mitigation strategies to address this issue include controlling rail surface irregularities through optimized rail grinding or milling procedures, using flash butt welding instead of thermit welding, using padded concrete sleepers, and encouraging the use of track-friendly vehicles with reduced unsprung mass through track access charge incentives.
Learn more about detecting minute rail surface irregularities and ways to mitigate them in the ASCE Library: https://ascelibrary.org/doi/10.1061/JTEPBS.TEENG-8973.
