Wolf GmbH, of Stuttgart was commissioned by DB Netz AG Hannover with the task of finding a quick but lasting solution for sealing a 46-metre long expansion joint against stone chippings and water flow. The railway bridge crosses the B522 highway to Hanover airport. Due to defective joint sealing tapes, the passage of trains causes small stones to fall through the 46-metre expansion joint onto the road below. Fortunately, this has so far not caused any accidents or serious damage.