The Wienerwald Tunnel is a 13.35 km (8.30 mi) long railway tunnel near Vienna, passing underneath the northern part of Wienerwald. It is part of a 250-kilometre-per-hour (160 mph) section between Vienna and St. Pölten which is part of Austria's Western Railway.

The Western Railway is a two-track, partly four-track, electrified railway line in Austria that runs from Vienna to Salzburg via St. Pölten and Linz Hauptbahnhof and is one of the major lines of Austria. It was originally opened as the Empress Elisabeth Railway in 1858 (Vienna–Linz). The line is owned and operated by Austrian Federal Railways (ÖBB).