Improvement of vehicle–turnout interaction by optimising the shape of crossing nose

Abstract

Proper rail geometry in the crossing part is essential for reducing damage on the nose rail. To improve the dynamic behaviour of turnout crossings, a numerical optimisation approach to minimise rolling contact fatigue (RCF) damage and wear in the crossing panel by varying the nose rail shape is presented in the paper. The rail geometry is parameterised by defining several control cross-sections along the crossing. The dynamic vehicle-turnout interaction as a function of crossing geometry is analysed using the VI-Rail package. In formulation of the optimisation problem a combined weighted objective function is used consisting of the normal contact pressure and the energy dissipation along the crossing responsible for RCF and wear, respectively. The multi-objective optimisation problem is solved by adapting the multipoint approximation method and a number of compromised solutions have been found for various sets of weight coefficients. Dynamic behaviour of the crossing has been significantly improved after optimisations. Comparing with the reference design, the heights of the nose rail are notably increased in the beginning of the crossing; the nominal thicknesses of the nose rail are also changed. All the optimum designs work well under different track conditions.

Robust optimisation of railway crossing geometry

“…In [3], it was observed from the field measurements that after grinding/welding maintenance of the crossing, not only was the magnitude of impact significantly reduced but also the location of impact was shifted -leading to wider spread of impacts on the nose rail. A close look at the geometric effect on the transition location has been documented in [12], in which it is shown that both the nose rail shape and the vertical distance between the top of the wing rail and the nose rail have considerable influence on the impact location.…”

“…The studied turnout is a standard one (right turn) with a curve radius of 725 m and a crossing angle of 1:15, which is the same model as in [3,12]. In the present paper, the investigations are only for a vehicle passing in the main-facing direction.…”

“…Studies in [1][2][3] show that the dynamic wheel transition over a crossing is very sensitive to changes in rail geometry and can be improved by adjusting the crossing geometry. Studies concerning numerical optimisation of the crossing geometry have been performed recently, [3,4] in which significant reduction of contact pressure and/or wear in the wheel-rail interface at a crossing has been achieved. These optimisation problems are formulated as deterministic optimisation problems, which tend to push a design towards one or more constraints until the constraints are active.…”

“…Moreover, deviation between a newly implemented design and a design in the service stage is inevitable; • F.2 Uncertain disturbances, i.e. parameters that influence the evaluated properties of the solution are not deterministic in the real-world; • F. 3 The design must remain feasible for allowable (tolerated) deviations of the optimum solution; • F. 4 Optimal solutions become severely unfeasible in the face of even relatively small changes in the input parameters of the problem.…”

Parameters Studies on Surface Initiated Rolling Contact Fatigue of Turnout Rails by Three-Level Unreplicated Saturated Factorial Design

“…In addition, they also evaluated the structural design of turnout switches based on this method. Markine, Wan and Wang et al [6][7][8] optimized the track stiffness and rail profiles in order to reduce the dynamic wheel-rail interaction at turnout zones and solve problems such as rail wear and fatigue of turnout rails. Pletz et al [9] presented a finite element model for crossing with a single running wheel according to the wheel-rail vibration, elastic wheel deformation and plastoelastic rail deformation, in order to calculate the dynamic wheel-rail interaction, then they also presented a simplified finite element model for calculating the dynamic wheel-crossing interaction [10], according to the influence of grid precision and calculation time, through setting appropriate grid sizes.…”