Influence of the Head Wind on Determining Braking Performance of Zacns Tank Wagon

From the aspect of safety, brakes of rail vehicles are an extremely important system on the vehicle. Braking performance affects the normal functioning of vehicles and interoperability of rail vehicles in classic railway train compositions. All trains, classic and different type of motor trains must conform with the available stopping distances, which are predefined by the railway signalling, i.e. control length of a signal and depends on the maximum allowable speed for which the track section is designed. Apart from that, in classic wagons, which are combined and participate in the formation of different train compositions, mutual compatibility must be ensured from the aspect of used braking equipment and connection subassemblies, but even more important, braking performance of all wagons in the train has to be uniform within certain tolerances. This prevents weaker braked wagons from running into stronger braked ones, which can cause longitudinal jerks and may in extremes lead to a train rupture. Stopping distance during brake application depends on train braking performances, longitudinal running resistance and presence of wind and its direction. This paper deals with the influence of wind conditions on the results of slip brake tests and the estimation of a single vehicle's braking performance. Based on experimental measurements, simulations using CFD and comparison with the obtained results, this paper proposes a possibility to extract air drag resistance and wind force from the total resistance force. Presented methodology and obtained results may serve for further simulations of aerodynamic characteristics apart from braking performance, such as vehicle running resistance, energy consumption, etc. and for optimization of the wagon shape and design.