Vialis NMA Railway Signalling designs, manufactures, installs and maintains  railway level crossing protection systems.  By Dutch law a railway barrier arm has to fall into its horizontal closing  position in case of an electrical grid failure to avoid any chance of an  accident. However, strong winds might keep the barrier arm open due to the  acting aero dynamical forces. This might not only be a problem for areas  close to the coast, where strong winds are common, but also in built-up  areas, where local wind gusts can occur between tall buildings. These  operational conditions have  resulted in a design requirement  for a streamlined barrier arm with low wind loading.  After Vialis NMA had produced a first prototype of such a barrier arm  FlowMotion has performed several tests in the Low Speed Wind Tunnel of  the Aerospace department of the  Delft University of Technology to  determine the relation between the air flow velocity around the barrier arm  and the generated aerodynamic forces. For this a part of the barrier arm  has been placed in the measurement section of the wind tunnel and  connected to a weighing system, which is able to measure 3 forces and 3  moments simultaneously with an accuracy of 0,01 Newton. This system  also allowed the barrier to be rotated around its longitudinal axis.  In addition to  the measurement of the forces acting on the barrier, it has  been investigated, whether the so-called “Von Karman vortex street” might occur. This has been done by measuring  the frequency spectrum of the passing flow using a microphone. In case the frequency of the vortex shedding is close  to the eigenfrequency of the barrier arm structure, it might start to vibrate  with an increasing amplitude, finally resulting in a total collapse of the  barrier arm. Having established the aerodynamic characteristics of the newly  designed barrier arm in the wind tunnel, subsequently its behaviour in an  open atmosphere has been analysed. In this study both various topologies  of the surrounding area as several weather conditions have been included.  In the latter case wind statistics from the Royal Netherlands Meteorological  Institute (KNMI) have been used.  From this project a barrier arm has emerged which not only has favourable static and dynamic behaviour during  various operational conditions but also has documented aerodynamic characteristics.  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 (1. part) Drag minmization for a railroad barrier We solve every Flow problem. Vialis NMA Railway Signalling www.vialis.nl railway barrier wind tunnel test