Arlberg Railway Tunnel

In the central part of the tunnel. It is possible to see the west mouth in six kilometres
Eastern end in 1894
A construction train at the Langen entrance.
Sign at the eastern end of the railway tunnel

The Arlberg Railway Tunnel (German: Arlbergtunnel) forms the central part of the Arlberg railway in western Austria, running between the federal states Tyrol and Vorarlberg. It traverses through the Arlberg massif at the northeastern end of the Rhaetian Alps.

First opened to traffic in 1884, it was a major engineering achievement of the nation, being the longest railway tunnel in Austria for over 100 years, possessing a length of 10,216 metres (6.348 mi). Originally operated by steam locomotives, the Arlberg Railway Tunnel was reengineered during the 1920s for use by electric traction. During the 2010s, further modifications were implemented to introduce improved safety levels and expand the loading gauge. It is interconnected with the later-built Arlberg Road Tunnel.