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Modeling the loading behavior of railway structure under static load using a verified 3D finite element model
Published in Inge Hoff, Helge Mork, Rabbira Garba Saba, Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 2, 2022
M. Peltomäki, P. Kolisoja, H. Luomala
In the created calculation model, the rails are modelled using one-dimensional beam elements and the calculation parameters used correspond to the 60E1 rail profile (SFS-EN 13674-1:2011); therefore value 210 GPa has been used as the modulus of elasticity of the rail steel, the rail cross section area is 0,00767 m2 and the second moments of cross section area are 3.055⋅10−5m4 for the vertical bending and 5.120⋅10−6m4 for the horizontal bending.
Wheelclimb Derailment Criteria Under Steady Rolling and Dynamic Loading Conditions
Published in H.-P. Willumeit, The Dynamics of Vehicles on roads and on tracks, 2018
Larry M. Sweet, Amir Karmel, Peter K. Moy
Three possible sources of error may account for this discrepancy, two experimental and one theoretical. In the vicinity of the derailment location on the track, local variation in rail profile curvature from nominal values may produce significant changes in nondimensional lateral creep coefficient f2,2⋅ Error in f2,2 or friction coefficient μ would produce an error in the predicted derailment limit. The third possible source of error results from the high ratio of the semi-axes of the contact ellipse in flange contact. For the wheel and rail profiles used in the experiment the ratio a/b is 16, which is beyond the numerical range computed by Kalker and the experimental range measured by Brickle [3]. Therefore numerical error in the calculated creep forces is not excluded as an explanation for the difference between theory and experiment.
Geometric analysis of wheel-switch for new and old turnout
Published in Maksym Spiryagin, Timothy Gordon, Colin Cole, Tim McSweeney, The Dynamics of Vehicles on Roads and Tracks, 2018
Xu Zhang, Gang Shen, Dilai Chen
For the rail vehicles, wheel rail contact geometry is the most basic problem in the railway traffic system. If the rail surface doesn’t match with the wheel profile, it will bring some serious problems to the operation of the train, such as instability, wear, wheel rail contact noise [1]. Besides, it is more complex for turnout. As wheel-rail contact points are discontinued and jump in longitudinal direction, the wheel rail contact geometry parameters change. The paper [2] studies wheel-switch two-point contact judgment and calculation method and the static contact between wheel and rail. There are four cases, including a single contact point (on the basic rail), a single contact point (on switch blade), two contact points, and three contact points. For the rail vehicle through the turnout, it will produce the so-called conformal contact [3]. Conformal contact refers to the contact, in a contact patch, the contact angle will occur significant change. Due to the vehicle dynamic behavior, it will produce tangential force and slip between wheel and rail, which causes the wear. In addition, the dynamic performance of railway vehicles will be affected by the wheel-rail interaction. Any tiny deviation of wheel and rail profile will influence the train running [4]. Wear will increase the wheel and rail conformal contact degree, making the worn wheel and worn rail are more susceptible to conformal contact. To a certain extent, it will reduce the wheel-rail contact stress. However, it will increase amplitude and fluctuation degree of the vertical wheel-rail contact irregularity [5]. In switch area, compared to the basic rail, switch blade wears faster.
Prediction of tram track gauge deviation using artificial neural network and support vector regression
Published in Australian Journal of Civil Engineering, 2019
Amir Falamarzi, Sara Moridpour, Majidreza Nazem, Samira Cheraghi
First, based on reviewing the relevant research, input variables are defined. There is a diverse range of parameters which can affect gauge deviation including track gauge deviation in previous year, curve radii, axle load or annual tonnage (in MGT), rail support (concrete and steel sleeper), track surface (asphalt and concrete), rail profile (41 kg, 43 kg, etc.), rail type (T-shaped and Grooved) and year of track installation. Track gauge is the spacing between inner faces of the railheads. Rail support is rectangular support, which used to maintain rail upright and keep the spacing to the right gauge. Track surface determines the type of materials used to fill the gap between rail tracks. Rail profile represents the cross-sectional shape of a rail which is represented by kilogram per metre. Rail type represents the shape of the railhead. In this research, the target variable is track gauge in the current year.
Investigating the influence of rail grinding on stability, vibration, and ride comfort of high-speed EMUs using multi-body dynamics modelling
Published in Vehicle System Dynamics, 2019
Kai Xu, Zheng Feng, Hao Wu, Fu Li, Chenhui Shao
As a result, this long-term investigation confirms that rail grinding has the potential to provide the following benefits. Through rail grinding, the rail profile is restored. As a result, as the differences in the rail profile along the running direction of the train decrease, the magnitude of the change in the lateral force of the wheel will be effectively decreased. As the left and right rail profiles become more consistent, the wheel-rail interaction improves. Proper wheel-rail equivalent conicity can prevent excessive vibration and ensure the running stability of the trains.Rail grinding improves the track irregularity level. The ride comfort is improved through a decrease in acceleration of the trains. In the follow-up test, the alert times of the vibration analyser were dramatically reduced, and all the indices of the track inspection car were improved. It also reduces the wheel/rail noise.After rail grinding, the surface roughness of the rail is reduced, so the running resistance, traction energy consumption, and power supply can be reduced. The wheel-rail contact fatigue is limited by rail grinding to eliminate the hardened layer. Meanwhile, the shape of the contact area becomes more regular. The wheel-rail contact points move towards the centre of the railhead, which leads to a centred running band, and avoids the double running band caused by contact between the gauge corner and wheel flange. After rail grinding, the width of the running band is limited to a range of 20–30 mm, which could reduce rail damage and prolong the service life of the rail.