The Pilatus Railway is a mountain railway in Switzerland and the steepest rack railway in the world, with a maximum gradient of 48% and an average gradient of 35%. The line runs from Alpnachstad, on Lake Alpnach, to a terminus near the Esel summit of Pilatus at an elevation of 2,073 m (6,801 ft), which makes it the highest railway in the canton of Obwalden and the second highest in Central Switzerland after the Furka line. At Alpnachstad, the Pilatus Railway connects with steamers on Lake Lucerne and with trains on the Brünigbahn line of Zentralbahn.

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.