Wetting a rail tanker behind a noise shield

In the Netherlands, the Betuweline is a dedicated freight railway. It will, among other things, be used for transportation of all kinds of hazardous materials from the Port of Rotterdam to the German Hinterland and vice versa. The line is approximately 150 km long. Alongside the line, over more than 100 km noise shields are apparent. The question is to what extent this noise shield hinders the cooling of a rail tanker, carrying flammable liquid such as liquefied petroleum gas (LPG)? To answer this question, a full scale test was conducted on an already constructed part of the Betuweline [N. Rosmuller, D.W.G. Arentsen, (2005). Praktijkproeven Betuweroute: Instantane uitstroming en koeling 24 juni 2005, Nibra, Arnhem, The Netherlands]. Two railcars and a rail tanker were placed behind a 3m high noise shield. First, it was tested as to whether firemen or water canons should be used to deliver the water. Water canons were best next, four positions of the water canons to wet the rail tanker were tested. Three camera's and three observers recorded the locations and the extent of water that hit the rail tanker. The results indicate that the noise shield, to a large extent, prevents the water from hitting, and therefore cooling, the rail tanker. The upper parts of the rail tanker were minimally struck by the water canons and the small amount of water flowing down the rail tanker did not reach the lower parts of it because of the armatures at the rail tanker. Also, the amount of water in the ditches to be used for wetting was too small. The ditch nearby ran empty. These insights are both relevant to emergency responders for disaster abatement purposes and to water management organizations. The Ministry of Transport is examining the possible strategies to deal with these findings. The results are based upon one single full scale test near a 3m high noise shield. In addition, it would be valuable to determine what the influence would be of other heights of the noise shields.