The Nerobergbahn was built in 1888 as a funicular railway driven by water counterbalancing and is still operated with this technology. It connects the Nerotal Valley with the Neroberg Hill, a lookout high over Wiesbaden. [German]
The technology of the Nerobergbahn
The Nerobergbahn works as a water ballast railway. The water ballast makes the mountain carriage heavier than the valley carriage. That way, the mountain carriage is able to pull the valley carriage up to the top. As a result, the funicular runs without any integrated power drive.