Monte Carlo modelling of frictional uncertainties in three-piece bogie hunting mechanisms

• Friction variations influence the vehicle dynamic behaviour and critical speed. • Loadings change the relationship between friction interfaces and critical speed. • High wheel-rail friction increases the risk of derailment in tare wagons. • Monte Carlo simulation for wagon fleets and railway performance studies. Modern multibody dynamics analyses of railway vehicles must account for the stochastic nature of friction coefficients, particularly in freight wagons with numerous friction interfaces. This is especially relevant for three-piece bogie vehicles, where friction behaviour significantly influences dynamic performance. However, most existing approaches rely on deterministic inputs, limiting their ability to reflect the variability in frictional characteristics that affect critical speed and other dynamic responses. This paper proposes a Monte Carlo simulation approach to model uncertainties in rail vehicle dynamics, enabling the exploration of diverse operational scenarios through randomised input parameters. When combined with high-performance computing, this approach allows for more comprehensive vehicle dynamics analysis compared to traditional deterministic approaches. A critical speed case study on a heavy haul vehicle demonstrates the proposed method's effectiveness. Friction coefficient variability critically influences the dynamic performance of rail vehicles, providing valuable insights for vehicle design, operational strategies, and maintenance practices. Wheel-rail interface and bogie centre plate bottom friction coefficients exert significant influence on vehicle stability, with the effects varying notably between laden and tare conditions.