Transient adhesion effects in rolling–sliding contacts influence all aspects of train–track interaction. This is of high importance specifically when these effects result in critically low adhesion, which poses a risk to traction and braking of railway vehicles. This study presents a model that can replicate the transient changes of the coefficient of adhesion with tested water and solid particle mix. The experimental data for the model are measured using a commercial ball-on-disc tribometer. The experimental results showed a liquid reservoir in front of the contact area that slowly reduces in size. This observation was used in the modelling approach to divide the calculation into two stages where the reservoir is present and when it disappears. The model was able to reproduce the occurrence of low adhesion region seen in experimental results with different particle concentrations.

Top-of-rail product assessment in terms of frictional properties plays a key role in the evaluation of desired benefits for wheel-rail contact. In this study, a high-pressure torsion device is used to study the friction-displacement properties of three types of top-of-rail products. The effects of applied amount and increased temperature were investigated. All tested products were very sensitive to the amount applied. For the water-based substance, the evaporation of water created a solid-like film that provided very low friction. The increase in temperature lowered the coefficient of friction for dry contact but had a negligible effect on the applied products. A FASTSIM-based numerical model is used to demonstrate the application of these results.

This study investigates the potential of water lubrication to reduce wheel squeal noise in tramway turnaround loops, focusing on low rolling speeds. A combination of experimental testing and simulation modelling was used to assess the effect of water on noise generation under varying rolling speeds, angles of attack and loads. Vibro-acoustic measurements identified dominant frequency modes and quantified noise levels in dry and wet conditions. The results show that water alters the noise dynamics by shifting the dominant frequency modes as a function of load and speed. Unlike dry conditions, wet SPL does not show a consistent monotonic increase with rolling speed. While water does not eliminate squeal, it reduces excitation, achieving 10-20 dB noise reduction at higher speeds but only 2 dB at lower speeds. The results support the quasi-static and instantaneous creep curve hypothesis, consistent with the studies of Liu and Meehan. This study provides evidence that water lubrication is an effective, environmentally friendly alternative to chemical friction modifiers for the reduction of squealing noise.