The Saint-Louis-Arzviller inclined plane is a part of the Marne-Rhine Canal. Located on the territory of the commune of Saint-Louis, between the towns of Saint-Louis and Arzviller in the department of the Moselle, it enables the canal to cross the Vosges Mountains. The structure opened in 1969, replacing a staircase of 17 locks to provide for a change in level of 44.55 metres (approximately 138 feet). The inclined plane comprises a single trough - called a caisson -, which moves laterally up or down the hillside on rails set at an angle of 22°- gradient 41%. The caisson is counter-balanced by two weights each of 450 metric tons, and the length of the lifting ramp is 108.65 metres (about 335 feet). The design is believed to be unique in Europe. Prior to the construction of the incline, barges needed 8 to 13 hours to traverse the 17 locks and 10200 cubic meters of water was needed to operate the series of locks. The incline can be traversed in 4 minutes and requires only 40 cubic meters of water. Because the design uses counterweights to balance the weight of the caisson being moved, the entire operation can be run by two 120 horsepower electric motors, which causes a small energy consumption. According to Archimedes' principle the barge, which enters the caisson, pushes back towards the canal a quantity of water equivalent to the mass of the barge. Thus, the caisson always weighs the same, whether or not it contains a barge. In principle, the system could function without <b>...</b>