The Austrian Southern Railway (German: Österreichische Südbahn) is a 577.2-kilometre (358.7 mi) long double track railway, which linked the capital Vienna with Trieste, the former main seaport of Austria-Hungary, by railway for the first time.

The viaduct was badly damaged during World War II and demolished completely a few years after.

The section from Graz to the Slovenian border (near Šentilj v Slovenskih goricah), which had been downgraded to a single track railway in the 1950s, is currently again rebuilt as a double track line.

On the Slovenian section, work is in progress to upgrade and renovate Pragersko railway station as well as the line and railway crossings from Maribor to Celje.

Infrastructure and transport management on the line is now provided by three railway companies: Austrian Federal Railways (ÖBB) for the Austrian section, Slovenske železnice (SŽ) for the Slovenian one, and Italian railway infrastructure manager Rete Ferroviaria Italiana (RFI) for the Italian section.