This is a list of mountain railways in operation in Switzerland. It includes railways that overcome steep gradients (over 5%) or whose culminating point is over 800 metres above sea level. Most of them are located in the Alps, which include the highest European railways, such as the Jungfrau and Gornergrat railways. Lines that are both adhesion and standard gauge railways and part of the main Swiss (and European) rail network are boldfaced in the list. Cantons where the line continues but does not fit the aforementioned criteria are indicated in small letters.