The Jungfraubahn (JB) is an 1,000 mm (3 ft 3 3⁄8 in) gauge rack railway electrified at 3-phase 1,125 volts 50 Hertz, which runs 9 km / 5,6 m from Kleine Scheidegg at 2,061 m / 6,762 ft. to the highest railway station in Europe at Jungfraujoch on 3,454 m / 11,333 ft. The railway runs almost entirely within a tunnel built into the Eiger and Mönch mountains and contains two stations in the middle of the tunnel, where passengers can disembark to observe the neighbouring mountains through windows built into the mountainside.