Recent trends in surface metrology

This literature survey discusses the state-of-the-art in research on why out-of-round railway wheels are developed and on the damage they cause to track and vehicle components. Although the term out-of-round wheels can be attributed to a large spectrum of different wheel defects, the focus here is on out-of-round wheels with long wavelengths, such as the so-called polygonalization with 1-5 harmonics (wavelengths) around the wheel circumference. Topics dealt with in the survey include experimental detection of wheel/rail impact loads, mathematical models to predict the development and consequences of out-of-round wheels, criteria for removal of out-of-round wheels and suggestions on how to reduce the development of out-of-round wheels.

Out-of-Round Railway Wheels - a Literature Survey

Suspension components play key roles in the running behaviour of rail vehicles, and therefore, mathematical models of suspension components are essential ingredients of railway vehicle multi-body models. The aims of this paper are to review existing models for railway vehicle suspension components and their use for railway vehicle dynamics multi-body simulations, to describe how model parameters can be defined and to discuss the required level of detail of component models in view of the accuracy expected from the overall simulation model. This paper also addresses track models in use for railway vehicle dynamics simulations, recognising their relevance as an indispensable component of the system simulation model. Finally, this paper reviews methods presently in use for the checking and validation of the simulation model.

Modelling of suspension components in a rail vehicle dynamics context

Safe life and damage tolerance aspects of railway axles – A review

Fatigue of Materials: Preface to the second edition

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 and suggested remedies to relieve the problems are discussed for three types of irregular wheel/rail wear: (1) short-pitch rail corrugation on tangent tracks and large radius curves, (2) wheel corrugation as caused by tread braking, and (3) wheel polygonalisation. The state-of-the-art in modelling of dynamic train-track interaction in conjunction with prediction of irregular wear is reviewed.

Train-Track Interaction and Mechanisms of Irregular Wear on Wheel and Rail Surfaces

Thermally induced roughness of tread braked railway wheels, Part 1: Brake rig experiments

Thermally induced roughness of tread braked railway wheels : a noise-related problem

A thermal model of railway tread braking is developed for use in routine calculations of wheel and brake block temperatures. Two-dimensional finite-element models of block(s) and wheel are coupled via a contact interface that controls the heat generation and also the heat partitioning between block and wheel through thermal contact resistances. The surface temperature variations around the wheel circumference as caused by frictional heating and intermediate cooling are accounted for in a mean sense, assuming high-speed sliding conditions. The thermal power generated at the block-wheel interface during braking is determined from train braking data. A model for heat transfer from the rolling wheel into the rail is developed where a film with thermal contact resistance is placed at the wheel-rail contact interface. The present model can be used to efficiently design tread braking systems for both freight and passenger trains. It can handle stop braking, drag braking at constant brake power, and also intermediate periods of cooling. The temperature history during a full train route can be calculated. The inclusion of heat transfer from wheel to rail means that the model is useful for comparing brake rig tests, where normally the chilling influence from the rail is not included, with in-field tests. Two companion papers with experimental results supplement the present numerical modelling. A brief numerical example demonstrates the heat partitioning and the influence of rail chill (about 30 per cent) for two braking configurations.

Temperatures at railway tread braking. Part 1: Modelling:

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

Tore V Vernersson

Papers

Train-Track Interaction and Mechanisms of Irregular Wear on Wheel and Rail Surfaces

Thermally induced roughness of tread braked railway wheels, Part 1: Brake rig experiments

Thermally induced roughness of tread braked railway wheels : a noise-related problem

Temperatures at railway tread braking. Part 1: Modelling:

Temperatures at railway tread braking. Part 2: calibration and numerical examples