Degradation of railway track geometry – Correlation between track stiffness gradient and differential settlement
Journal article, 2018

Based on the track geometry car recordings performed from 1999 to 2016 on a section of the Swedish heavy haul line Malmbanan, the vertical track geometry degradation is analysed for wavelengths in the interval 1–25 m. The upper layer of the subgrade on parts of the rail section is peat (depths of up to 2 m), while it is moraine on others leading to a significant longitudinal variation in substructure stiffness. The degradation rates of irregularities in the longitudinal level and the influence of track maintenance (tamping) on the track geometry are studied. In parallel, a method for continuous measurement of track vertical stiffness along the line, allowing for the detection of track sections with poor support conditions, is described and demonstrated. Synchronised measurements of the longitudinal level and the track vertical stiffness are evaluated to determine whether there is a correlation between a high stiffness gradient due to variations in substructure stiffness and a high growth rate of local track geometry irregularities. It is shown that recurrent severe local track geometry irregularities often occur on track sections where there is a combination of a low magnitude and a high gradient in the substructure stiffness. In such cases, tamping may not be a cost-efficient long-term solution to the problem. Instead, upgrading of ballast and subgrade layers should be considered as an option. It is concluded that measurement of track vertical stiffness is an efficient method for the maintenance planning of a more robust railway track, which also minimises the life cycle cost and environmental footprint.

Maintenance planning

stiffness gradient

track stiffness measurement


track geometry degradation


Jens Nielsen

Chalmers Railway Mechanics (CHARMEC)

Chalmers, Mechanics and Maritime Sciences

Eric G. Berggren

EBER Dynamics AB

Anders Hammar

Swedish Transport Administration

Fredrik Jansson

Swedish Transport Administration

Rikard Bolmsvik

Abetong AB

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit

0954-4097 (ISSN)

Vol. 234 1 108-119

Subject Categories

Infrastructure Engineering

Vehicle Engineering

Signal Processing



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