Years ago Vialis NMA Railway Signalling has gone an entirely new way to develop  railway barriers. This innovative barriers have a decisive advantage compared to  the products of other competitors in the market. Because of the aerodynamically  optimized shape the barrier always falls into the traffic protecting horizontal  position in case of an energy break down. In the development process of this  barrier FlowMotion has performed  intensive wind tunnel tests to minimize the  forces, which would keep the barrier in an upright position for certain wind  directions.  In these wind tunnel tests a 1m segment of the  barrier has been connected to a force and  moment measuring system, to determine the relation between wind speed and  direction and the resulting forces. The primary target of the current study was to  determine the forces and moments for real wind conditions and all possible positions  of different barrier with respect to the ground. To maximize the accuracy all fluid  dynamical effects like vortices at the inner structure and the barrier tips has been  taken into account.  Due to the large number of different cases (barrier geometry, wind speed, wind  direction, position of the barrier) and since only vertical positions could have been  investigated in a wind-tunnel, flow simulations (CFD Computational Fluid Dynamics)  has been used to obtain the required data.  In these numerical study the real 3D  geometry of the barrier has been modelled in the computer, the flow field has been  simulated and the forces have been calculated by data post processing.  The accuracy of the simulation has been determined by comparing the previous  results of the wind tunnel test with an equivalent simulation of the wind tunnel flow.  Within the scope of the project the comparison has shown a good agreement  between the simulation and the measurements, although the geometry of the barrier  is rather complex. In the simulation even smallest rag producing geometrical details  have been taken into account. The found vortices in the flow field along the  framework structure of the barrier underline the necessity of this highly detailed  modelling.  The calculation of the forces for each barrier and wind conditions and the  visualization of the causing fluid dynamical effects helps Vialis to position their  products in the rapid changing market of the future.  Offices: The Netherlands Leeghwaterstraat 21 2628 CA Delft Tel.: +31 15 278 2907 Germany Weenermoorer Str. 193 26826 Weener Tel.: +49 4953 922 969 Consultancy for Heat Transfer and Fluid Dynamics CFD makes fluid dynamics visible. ANSYS Gone with the Wind (2. part) Calculation of the aero dynamic forces on a railroad barrier We solve every Flow problem. Vialis NMA Railway Signalling www.vialis.nl flow around the railway barrier wind tunnel test