Wheel squeal: Insights from wayside condition monitoring

Abstract

This paper summarises the insights gained by analysing wayside condition monitoring data from a curve of 300 m radius in Sydney over a three year period. The aim of analysing a large dataset is to derive statistically significant results on how angle of attack, speed, rail lubrication and rail grinding influence wheel squeal. The key finding is that the generation of severe wheel squeal is strongly determined by the angle of attack, which is consistent with the theory: severe squeal was almost entirely absent when the angle of attack was less than 10 mrad, and rose with increasing angle of attack. Squeal was therefore associated only with basic three piece bogies as these were the only bogies to return high angles of attack. Other freight bogie types, such as the one-piece freight bogies, three-piece freight bogies fitted with cross-bracing or steering arms, all steered well around the curve and did not squeal. Other factors, such as speed, rail lubrication and rail grinding, would influence wheel squeal generation when combined with high angles of attack. These factors were found to influence squeal behaviour, but are secondary for controlling wheel squeal compared with solving the poor steering performance of the three-piece freight bogies.