Brake system represents an important aspect of the vehicle dynamics apart from being an active safety system. The vehicle retardation and stopping distance completely depend upon the performance of brake system and the functionality of all components. However, the performance prediction of the entire system is a challenging task especially for a complex configuration such as multi-axial vehicle applications. Furthermore, due to its complexity most often the performance prediction by some methods is limited to static condition. Hence, it is very important to have equivalent mathematical models to predict all performance parameters for a given configuration in all different conditions. This paper presents the adopted system modelling approach to model all the elements of the pneumatic brake system such as dual brake valve, relay valve, quick release valve, front and rear brake actuators, foundation brake etc. The commercially available multi-physics tool LMS AMESim was used for building mathematical models. The results from these models such as transient pressure response during braking, stopping distance, deceleration of a vehicle were tested and validated with the experimental data for different applications. Using these models, the overall braking architecture and the corresponding elements have been optimised for performance and cost efficiency.