Simulation and understanding the wet-rail phenomenon using twin disc testing

Low adhesion due to the wet-rail phenomenon is a year round problem for the rail industry. It is thought to occur due to wear debris and iron oxides combined with small amounts of water, often from dew or light rain. It occurs without visible contamination and the transient, low moisture conditions mean that it has previously been difficult to study and has not been simulated in a laboratory, which limits understanding and inhibits the development of mitigation methods. This work simulates the wet-rail phenomenon on a twin disc test rig for the first time and concludes that iron oxide and water alone can form a paste and produce low traction values that are comparable to oil or leaf contamination.