Geometrical degradation of railway turnouts: A case study from a Swedish heavy haul railroad

Abstract

Turnouts are critical components of track systems in terms of safety, operation and maintenance. Each year, a considerable part of the maintenance budget is spent on their inspection, maintenance and renewal. Applying a cost-effective maintenance strategy helps to achieve the best performance at the lowest possible cost. In Sweden, the geometry of turnouts is inspected at predefined time intervals using the STRIX / IMV 100 track measurement car. This study uses time series for the measured longitudinal level of turnouts on the Iron Ore Line (Malmbanan) in northern Sweden. Two different approaches are applied to analyse the geometrical degradation of turnouts due to dynamic forces generated by train traffic. In the first approach, the recorded measurements are adjusted at the crossing point and then the relative geometrical degradation of turnouts is evaluated by using two defined parameters, the absolute residual area and the maximum settlement, In the second approach, various geometry parameters are defined to estimate the degradation in each measurement separately. The growth rate of the longitudinal level degradation as a function of million gross tonnes / time is evaluated. The proposed methods are based on characterisation of the individual track measurements. The results facilitate correct decision-making in the maintenance process through understanding the degradation rate and defining the optimal maintenance thresholds for the planning process. In the long run, this can lead to a cost-effective maintenance strategy with optimised inspection and maintenance intervals.

Measurement of the Geometric Center of a Turnout for the Safety of Railway Infrastructure Using MMS and Total Station

“…Khouy et al [ 12 ] argued that each year, a significant part of the budget should be devoted to the inspection, maintenance, and renewal of turnouts. The application of a cost-effective maintenance strategy can help achieve the best performance at the lowest possible cost.…”

An integrated methodology for the prognosis of ballast degradation in railway turnouts

“…5 Few studies have addressed the degradation modeling using historical data in turnouts. 2,6 Yet, the importance and criticality of such systems call for the advancement of degradation models specialized for turnouts.…”

“…48 Specific to geometry degradation at the crossing point in turnouts, indices like the absolute residual area (ARa), the maximum settlement (Smax), and surface roughness have been investigated. 6 All these indices are based on the track longitudinal level. Therefore, the index for ballast quality should be calculated from track longitudinal measurements, and it should reflect the wavelength content of the track vertical irregularities.…”

Three‐dimensional modelling of differential railway track settlement using a cycle domain constitutive model

“…The influences of the number of adjacent sleepers accounted for in the model and the stiffness of the subgrade on the predicted settlement at the crossing are studied. THREE-DIMENSIONAL MODELLING OF DIFFERENTIAL RAILWAY TRACK SETTLEMENT 1759 construction activities, leading to differential settlement and structural damage of adjacent buildings was investigated in [6].Railway crossings are particularly prone to differential track settlement because of the design of the crossing panel and the character of the impact loads induced by the transfer of wheels from wing rail to crossing nose [7,8]. Poor quality in track geometry induces high magnitudes of dynamic wheel-rail contact forces and increases the degradation rate resulting in increased damage of the rails, and further track settlement; see Figure 1.…”

“…Railway crossings are particularly prone to differential track settlement because of the design of the crossing panel and the character of the impact loads induced by the transfer of wheels from wing rail to crossing nose [7,8]. Poor quality in track geometry induces high magnitudes of dynamic wheel-rail contact forces and increases the degradation rate resulting in increased damage of the rails, and further track settlement; see Figure 1.…”