A study into the effect of the presence of moisture at the wheel/rail interface during dew and damp conditions

Incidents involving low levels of adhesion between the wheel and rail are a recurrent issue in the rail industry. The problem has been mitigated using friction modifiers, but a significant number of incidents still occur. The following work looks at the environmental conditions that occur around these low adhesion events in order to provide an insight into why they occur. Network Rail Autumn data, which provided details on the time and location of low adhesion incidents, was compared against weather data on a national and then local scale. Low adhesion incidents have often been attributed to contamination on the rail, such as organic leaf matter, but other incidents occur when no contamination is visible. The time, date and location of incidents were linked to local weather data to establish any specific weather conditions that could lead to these events. The effects of precipitation, temperature and humidity on the rail were analysed in order to further the understanding of low adhesion in the wheel-rail contact, which will lead to better methods of mitigating this problem.