Effects of temperature and humidity on railhead friction levels

This paper explores the research gap involving the links between railhead temperature, relative humidity, and coefficient of friction (adhesion level) at the wheel/rail interface as found on track across the UK. Existing work done in this field has mostly been carried out in laboratories which limits variation of environmental conditions. Weather and friction data were collected from different sites across England, generating a real representation of the railhead conditions. Correlations were established between the environmental dataset and the railhead friction to give a greater insight into the mechanisms of low adhesion and when low adhesion can be expected to take place. This can provide an avenue to better predict the occurrence of low adhesion in the wheel/rail interface, therefore improving safety within the rail network. Results from the data analysis showed that high humidity conditions, independent of the railhead temperature, reduces the adhesion level on the railhead. Showing that low adhesion can occur in warmer temperatures, such as those typically experienced in early autumn where there is high relative humidity.