Festungsbahn, Funicular railway in Salzburg, Austria

Festungsbahn is a funicular railway in Salzburg running from Festungsgasse in the left old town up to Hohensalzburg Fortress. Its 198.5 m track climbs 96.6 m at a maximum gradient of 60 percent, with a gauge of 1040 mm and an Abt passing loop at the midpoint. A riveted steel lattice bridge from 1892 still carries the track.

The Festungsbahn opened in July 1892 as a water-balance funicular run by the Salzburger Eisenbahn- und Tramwaygesellschaft, nicknamed the "Tröpferlbahn". It replaced the climb to the fortress, then used as barracks. The water-powered line closed on 18 October 1959; an electric railway with new cars opened on 16 April 1960. Stations were rebuilt in 1974–1976, cars and drive renewed in 1991–1992, and the line modernised again in 2011 for €4 million.

The lower station on Festungsgasse stands where the house of Michael Haydn, Joseph Haydn's brother, once was; it was also the birthplace of composer and pianist Joseph Woelfl (1773–1812). The line's early nickname, "Tröpferlbahn", came from its water-ballast drive, fed by the Stitsarmstollen of the Alm canal. Since 2000 the line has run under the FestungsBahn brand of Salzburg AG.

The ride takes roughly one minute to reach the top, making it a fast way to avoid walking up steep steps. Boarding happens at street level on Festungsgasse, and the railway operates every day as a practical shortcut to the fortress.

The 1892 riveted steel lattice bridge still carries the track, and the passing loop halfway up is an Abt switch, where the single track briefly becomes four rails. The Mönchsberg request stop there is now used only in special cases. The lower station stands above the Alm canal's water tunnel, visible in the rock in recent years.