Due to its weight, a train requires a low gradient, which normally means cuttings and switchbacks in mountainous terrain. However, reaching the top of mountain is another matter, since removing removing the summit is not an option, and one of the ways of scaling such steep inclines is a funicular. Almost most of you will have heard the term, but how many know what it really means? It is essentially two trains operated on the counterbalance system. The ascending and descending lines form a loop, and the two trains are linked by a continuous cable. As one train goes down, its weight pulls the other one up. Sometimes, at the top, water is added to the descending train to increase the weight. Of course, the locomotive must still be powered - there is no such thing as a perpetual motion machine - but gravity significantly reduces the power bill.
However, in late 1897, in the Austrian Alps, a single rail line was introduced driven, not by steam or electricity, but by a balloon!
