The dynamic analysis of railway vehicles involves the construction of three independent models: the vehicle model, the track model, and the wheel-rail contact model. In this work, a multibody formulation is used to describe the vehicle model. A methodology is also proposed in order to create detailed track models, which include the flexibility of the rails and of the substructure. The inclusion of flexible track models is very important to study the dynamic behaviour of railway vehicles, especially the impact of train operations on the infrastructure and the damages on vehicles provoked by the track conditions. This topic has a significant economic impact on the vehicles maintenance and life cycle costs of tracks. The wheel-rail contact formulation proposed here allows obtaining, online during the dynamic analysis, the contact points location, for any threedimensional motion. In this work a post-processing tool is also developed to assess if a given vehicle is conform to the norms and regulations in practice and allows assessing quantitatively the dynamic behaviour of the vehicle in different operation conditions, being used for vehicle approval.