The Jungfraubahn (JB) is an 1,000 mm (3 ft 3⅜ in) gauge rack railway electrifie at 3-phase 1,125 volts, which runs 9 kilometres from Kleine Scheidegg to the highest railway station in Europe at Jungfraujoch. 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.