The Effects of Renewal and Tamping on Ballast and Track Geometry in Turnouts

Abstract

The geometry of ballasted railway tracks is subject to gradual deterioration with the accumulated passing tonnage. Tamping is a corrective maintenance to restore track geometry to a good condition. A model of renewal/tamping effect in combination with track geometry degradation models is an integral part of track life-cycle cost analysis. However, the effect of renewal/tamping on track geometry in terms of the amount of improvement in different geometry parameters is not certain. Moreover, the effects of tamping on the degradation of ballast is of interest. Statistical models are needed to explain the uncertainty of these effects. This study investigates the effect of renewal/tamping in railway turnouts and puts forward a model for quantification of its uncertainty. The data from loaded geometry recordings are used. The study uses fractal analysis of track longitudinal level to distinguish between the effects of renewal/tamping on different wavelength contents of the geometry measurements and hence it quantifies the effects on ballast degradation. Furthermore, the influencing factors on renewal/tamping effect are specified and their contributions are quantified.