Out-of-round railway wheels and polygonisation

Abstract

Out-of-roundness in railway wheels, in particular polygonal wear resulting in regular, multi-lobed, out-of-round wheels, has become a significant problem in recent years. It is of concern to railway operators due to the increased noise and vibration it can cause. This polygonisation is caused by cyclic wear but the exact mechanism leading to this type of wear is not fully understood. It appears to be the result of dynamic linking between a resonance or other periodic excitation in the coupled vehicle–track system and the existing wear at the wheel. This paper reviews the developing body of research being carried out in many countries by research groups, manufacturers and operators. Some examples of polygonisation on different types of railway vehicles are reported including feight trains, urban transit trains and high-speed trains. The main theories for the formation mechanisms are presented and the current measurement methods, computer simulation techniques and the effects and potential mitigation methods are reviewed. In parallel, the mechanisms and consequences of discrete wheel tread irregularities, such as wheel flats and material fall-out due to rolling contact fatigue cracking, are addressed.

KEYWORDS:

• Out-of-round railway wheels
• polygonisation
• polygonalisation
• railway wheel damage
• discrete wheel tread irregularities
• wheel–rail interaction and impact loads

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors acknowledge the support of the National Natural Science Foundation of China [grant numbers 52002342, 51875484, U21A20167, U1734201 and 51805450] and the support provided by the European Union Horizon 2020 research and innovation programme in the Shift2Rail project In2Track3 [grant agreement number 101012456]. Input to the survey on wheel–rail impact load alarm limits was provided by Matthias Asplund (Swedish Transport Administration), John Cookson (Monash University, Australia), Hannu Heikkilä (Finnish Transport Infrastructure Agency), Andrew Lyle-Carter (Network Rail, UK), Urs Schönholzer (Swiss Federal Railways), Bas van Wijhe (Prorail, The Netherlands).