The Cowburn Tunnel is at the the Western end of the Vale of Edale in the Derbyshire Peak District. The tunnel takes the Hope Valley Line under Colborne (part of a 1700ft moorland between Kinder Scout and Rushup Edge) to re-emerge near Chinley. It has a length of about 3.35km and was built in the mid 1890s.
In the 1970s this railroute was controversially given precedence over the more modern Woodhead route (which had then only recently been re-engineered and electrified), as the preferred passenger route between Manchester and Sheffield.