Mountain railway

A mountain railway is a railway that operates in a mountainous region. It may operate through the mountains by following mountain valleys and tunneling beneath mountain passes, or it may climb a mountain to provide transport to and from the summit.

Mountain railways often use narrow gauge tracks to allow for tight curves in the track and reduce tunnel size and structure gauge, and hence construction cost and effort. Where mountain railways need to climb steep gradients, they may use steep grade railway technology, or even operate as funicular railways.