Making maximum use of restrictive loading gauge as applied to friction damped freight vehicles

The presence of highly non-linear friction damping in the suspensions of many freight vehicles reduces prediction accuracy when using traditional kinematic gauging techniques. These techniques, which are often applied to the more linear behaving passenger vehicles, are based on the quasi-static suspension behaviour. Due to this limitation and a market requirement for cost effective and rapid vehicle gauging, the current approach in the UK for freight vehicles is to use static vehicle gauges. This method can be very conservative and lead to in-efficient use of the available space between vehicle and infrastructure. Computer simulation-based dynamic gauging techniques offer a way to maximize the use of the space available, by introducing into the gauging analysis, the dynamic behaviour of the vehicle. This paper describes the process of dynamic gauging for friction damped freight vehicles. The benefits of this method in terms of potential increase of the vehicle size are shown, but also difficulties within the process, especially concerning the adequate validation of the simulation models.