The Furka Steam Railway is a largely volunteer-operated heritage railway which operates a partially rack and pinion-operated line across the Furka Pass, between Realp in Uri and Oberwald in Valais. Culminating at 2,160 metres (7,087 ft), above sea level, it is an old mountainous section of the Furka Oberalp Bahn (FO) that was abandoned after the construction of the Furka Tunnel. It has been gradually brought back into service by the Verein Furka-Bergstrecke with the use of only steam locomotives, with the entire line completed in 2010. As a result, the nearly 18 kilometre-long Furka Railway is the longest operated unelectrified line in Switzerland. It is also the second highest rail crossing in Europe, after the Bernina Railway.
The section of line was always a severe operational difficulty for the FO as its high altitude rendered it impassable due to snow and ice for much of the winter season, hence its being abandoned and a tunnel constructed. This has remained a headache for the DFB, as every year it must be closed down and then reopened, an expensive process which involves the removal and replacement of a specially folding transportable bridge that would otherwise be damaged by the snow every year.
The rebuilding of the line has also not been without new difficulties. Requiring to cross a busy main road on a rack operated section, the rack over the road is retractable, actuated to raise at the same time as the level crossing barriers by radios fitted to the line's locomotives. Another section, running through a forested nature reserve, has had to be fitted with a sprinkler system that operates before and after trains pass, again actuated by the radios aboard. Relays allow the system to cascade up or down the section in line with the train, to save water which is supplied by natural water supplies near the summit of the line. (Wikipedia)