To enhance the operational safety of railway vehicles, sand spreading systems are tested in depots before deployment on the rail network. For this purpose, vehicles are positioned on specific tracks equipped with braking sand extraction systems.

At the bogie or wheel, a suction funnel is installed around the track, with the track running centrally through the funnel. The number of funnels depends on the number of wheels requiring braking sand application. The funnels are designed with dimensions allowing for a positioning tolerance of +/- 30-40 cm.

The spreading systems are activated, and one or more employees visually inspect whether braking sand flows correctly. Some sand immediately falls into the funnels, while most remains on the track and must later be manually swept into the funnel. In advanced setups, optoelectronic systems can detect and evaluate the sand remaining on the track.

A significant advantage of this extraction system is the reduced dirt and sand accumulation in work pits, which protects oil separators and minimizes the risk of slipping accidents.

The suction funnels are connected via a shut-off valve to a pipeline leading to the suction unit, which sequentially vacuums each funnel. Since the extracted material contains not only sand but also other debris, it must be disposed of. Reusing the sand is not feasible.