Water balance railway

A Water balance railway is a funicular, aerial tramway or cable railway that uses the weight of water to move its carriages.
The oldest water balance railway was probably the Prospect Park Incline Railway opened in 1845 at the Niagara Falls in the United States. It was later converted to electric operation and was shut down after an accident in 1908.
The oldest railway in Europe is the Giessbachbahn, which opened in 1879 and was converted to electric operation in 1948. The Bom Jesus do Monte Funicular was opened in Braga (Portugal) in 1882, which is the oldest railway that is still operating as a water balance.
In Germany, the last operating water balance railway is the Nerobergbahn in Wiesbaden. In Switzerland there is only one train left, the Funicular Neuveville–Saint-Pierre in Freiburg.
The two carriages of the facility are connected by a rope or cable that runs over a pulley in the mountain station. The carriages maintain approximately balance, so propelling the wagon requires only applying the force to unbalance the system. This is done by artificially increasing the mass of the car standing in the mountain station with water, so that the gravity acting on this additional mass can move the train.
Both cars therefore have a ballast water tank. Between two rides, water is filled into the tank of the carriage in the mountain station, while the tank of the carriage in the valley station is emptied. The upper, heavier vehicle driving down the valley now pulls the lower, lighter one up the incline. The amount of water required depends on the weight difference between the two cars, which is assumed to be around 80 liters for each passenger. Because the length of the rope and thus the weight of the rope between the sheave and the wagon going down the valley increases steadily while the rope is moving uphill, the speed must be regulated while driving. This is done with brakes in the vehicles, which usually act on a rack in the track bed, and especially in longer systems also by draining water from the wagon going down the valley. Some lifts have a lower rope to compensate for the weight of the rope, which is also guided over a pulley in the valley station.
The water required for the operation of the railway was usually taken from a body of water near the mountain station. In places where water from the area was not available at the mountain station, this was pumped from the valley station with pumps through a pressure line running along the route into a reservoir at the mountain station.
The track system is usually single-track and has a passing point in the middle. Due to the special switch construction of the Abtschen Weiche, each car is automatically guided to one of the two sidings. The narrow route reduces the space required and the effort involved in building bridges and tunnels.
Although the water was cheap to come by (unless it had to be pumped up to the mountain station, which required energy to do so), there were disadvantages to operating with water ballast. Winter operation became dangerous as soon as there was a risk of the water tanks or the brake rack icing up. Likewise, the forced break that was necessary until the next trip due to refilling proved to be disadvantageous. In addition, the high operating weight and the high axle load of the wagons increased the maintenance effort for the entire system. Because of these limitations, only a few water-ballast-operated railways were built; and most have been converted to electric operation or have been discontinued.
(sorted by opening year)
Only a few examples are listed here, as many Railways were first operated with water ballast.
(complete list of all funiculars in public passenger transport)