Crosswind stability of rail vehicles has been a research area for several decades, mainlymotivated by vehicle overturning accidents and higher speeds, but in recent times also byissues of lower energy consumption and track maintenance costs demanding lower vehi-cle weights. During everyday operation, rail vehicles are subjected to substantial lateralinfluences from track curves, track irregularities and crosswind, leading to large suspen-sion deflections and increased crosswind sensitivity. Unsteady crosswind like gusts alsocalls for attention. Simulations of possible vehicle overturning are necessary, but needto take large deflections and high shear in the suspension into account. If they deliverreasonable results, simulations represent an important tool for overturning predictionof rail vehicles.In the present work, multibody simulations of a high-speed rail vehicle under large lat-eral influences from track curves and track irregularities have been carried out, using ahalf-vehicle model in 2D and a full vehicle model in 3D, including different suspensionmodels. Corresponding field measurements of the relative lateral and vertical deflec-tions in the secondary suspension were performed on a fast train and used to validatethe multibody simulations.The 3D vehicle model was further used to study the vehicle response to unsteady cross-wind during curve negotiation, including aerodynamic loads obtained from unsteadyComputational Fluid Dynamics. In addition, the Quasi Transient Gust Modelling methodwas evaluated. Strong lateral and roll responses of the vehicle and influences of the gustduration and the relative difference between mean and maximum wind speed were ob-served. The influence of the vehicle’s suspension and mass properties on crosswindsensitivity were studied in addition.In order to validate modelling and simulation results for gust-like loads on a rail vehi-cle, full-scale experiments were conducted by exciting the carbody of a stationary railvehicle, imitating synchronous and asynchronous crosswind-like loads and measuringthe vehicle response. The measurements were reflected in multibody simulations, whichwere in good agreement with the measured responses. Parameter studies of the suspen-sion characteristics were performed additionally. Asynchronous crosswind-like loadswere in comparison to synchronous loads observed to result in lower wheel-unloadingIt was further studied whether active secondary suspension can be used to improve cross-wind stability. A fast rail vehicle equipped with active secondary suspension for ridecomfort purposes is exposed to crosswind loads during curve negotiation by means ofsimulations. For high crosswind loads, the active suspension is used to reduce the impactof crosswind on the vehicle. The control input is taken from the primary vertical sus-pension deflection. Three different control cases were studied and compared to the onlycomfort-oriented active secondary suspension and a passive secondary suspension. The application of active suspension resulted in significantly improved crosswind stability.