Summary High-frequency train-track interaction and mechanisms of wheel/rail wear that is non-uniform in magnitude around/along the running surface are surveyed. Causes, consequences suggested remedies to relieve problems discussed for three types irregular wear: (1) short-pitch rail corrugation on tangent tracks large radius curves, (2) wheel as caused by tread braking, (3) polygonalisation. The state-of-the-art modelling dynamic conjunction with prediction reviewed.

In this paper, an effort has been made to characterise and evaluate the risks caused by global uneven heating, which can occur on tread braked railway wheels during prolonged braking. Brake rig experiments a field study were performed exposed brake power levels corresponding down-hill The testing was at test Chalmers University, with controlled constant of three different types freight wheels. Ofoten Line outside Narvik, where wheel temperatures measured thermographically. It is found that...

To investigate the impact of localised heating phenomena in form hot spots on wheel performance general and residual stress state particular, a combination experimental testing finite element simulations tread braked wheels has been performed. Using newly established full-scale railway brake test rig, is exposed to prolonged drag braking applications at constant power levels induce high temperatures tread. The distribution evolution temperature studied using high-speed, high-resolution...

A thermal model of railway tread braking is developed for use in routine calculations wheel and brake block temperatures. Two-dimensional finite-element models block(s) are coupled via a contact interface that controls the heat generation also partitioning between through resistances. The surface temperature variations around circumference as caused by frictional heating intermediate cooling accounted mean sense, assuming high-speed sliding conditions. power generated at block-wheel during...

A better understanding of the thermomechanical loading brake discs is important for controlling material fatigue and crack propagation in disc. In present study, full-scale drag braking experiments were performed on made from eight different grey cast iron alloys. The well-performing materials also tested with an alternative pad material. testing procedure repeated brakings was used. disc temperatures registered by thermocouples embedded at selected locations, surface a thermocamera....

Temperatures in wheels and brake blocks at railway tread braking are studied under rig conditions. Results from experiments reported for drag constant power made of cast iron sinter composite materials. The influence block configuration, power, speed is studied. A thermal model braking, developed a companion paper, calibrated using the experimental data. This analyses wheel temperatures also partitioning heat between tests. Numerical examples indicate type on wheel-block partitioning. rail...

Abstract Dynamic wheel–rail contact forces induced by a severe form of wheel tread damage have been measured impact load detector during full-scale field tests at different vehicle speeds. Based on laser scanning, the three-dimensional geometry is employed in simulations dynamic vehicle–track interaction to calibrate and verify simulation model. The relation between magnitude various operational parameters, such as speed, lateral position contact, track stiffness within sleeper bay,...

Tread braking generates high temperatures in railway wheels and brake blocks as the kinetic energy of running train is transformed into heat. The induced components are here analysed with particular focus on cooling influence from rolling contact between hot wheel a cold rail. Controlled rig tests reported, where studied using so-called rail-wheel braked wheel, along results field tests. data these experimental studies used for calibration simulation tool calculation block temperatures....

The temperature rise of wheels and blocks due to frictional heating during railway tread braking along with the transfer heat through wheel–rail contact is studied in this paper. In particular, partitioning between block, wheel rail for stop cycles considered. are interest because they a limiting factor systems. Two types thermal models employed investigate maximum temperatures over tread. circumferential (plane) model wheel, block rail, problem by use finite element formulation...

A combination of instrumented wheelset measurements and numerical simulations axle bending stresses is used to investigate the consequences evolving rolling contact fatigue (RCF) damage on a passenger train wheelset. In field test campaign, have been monitored using with four strain gauges mounted axle, while evolution wheel tread (out-of-roundness) has measured regular occasions. The signals are post-processed in real time stress variations computed. Based convolution integral approach,...

A numerical study is presented where the impact of simultaneous thermal and mechanical loading on a railway wheel tread, as imposed by braking rolling contact, reported. comparison made two-dimensional (2D) 3D finite-element simulations thermomechanical problem featuring material model that accounts for expansion plastic deformations. It found 2D give unrealistic predictions The demonstrate significant influence also in cases rather moderate temperature increases. In particular, combination...

Wheel–rail impact loads generated by discrete wheel tread irregularities may result in high dynamic bending stresses the wheelset axle, leading to a decrease component life and an elevated risk for fatigue failure. In this paper, versatile cost-efficient method simulate vertical interaction between railway track, accounting generic distributions shapes of damage, is presented. The (comprising two wheels, axle any attached equipment braking power transmission) track with discretely supported...

The paper illustrates how damage patterns in the form of rolling contact fatigue (RCF) on wheels, can be employed to identify and improve underlying operational conditions. focus is RCF locomotive wheels operating Iron Ore Line northern Sweden Norway. Seasonal changes are charted. Potential root causes for observed identified investigated. Mitigating actions proposed efficiency implemented quantified.

Tread braking of railway wheels results in the kinetic energy train being dissipated into wheel and blocks form heat. This heat is further conducted adjacent structures, notably cold rail, also transferred surroundings by convection radiation. Heat partitioning between block is, for short time periods, controlled local thermal interactions at contact point conductive properties bodies. However, a metro that performs longer periods intermittent (or drag braking) convective radiation cooling...

The development of fatigue life assessment models for vehicle components exposed to thermomechanical supports the establishing adequate maintenance intervals that neither cause unnecessary downtime, nor jeopardize function components. In modern automotive applications, braking is closely related safety and commonly performed with disc brakes. Failure here may result in structural damage or even breakdown loss lives. present work, cyclic response grey cast iron analysed brake discs made from...

Design and standardization of railway axles from the mechanical-strength point view is discussed a brief state-of-the-art survey given. Traditional fatigue design with ‘safe-life’ approach more recent crack-propagation/defect-tolerance are described compared. Axles standard freight wheelset (22.5 tonne axle load) two heavy haul wheelsets (25 31 loads) used for illustration. From numerical results it concluded that could be useful complement to traditional method. A result particular interest...