SOUGH TUNNEL

A helicopter has been used to repair a historic Victorian railway tunnel that takes passenger trains between Clitheroe and Manchester through a hillside in Darwen, Lancashire.
As part of Sough tunnel’s charm, it has two shaft turrets that protrude out of the Darwen moors. They help release air pressure created inside by moving diesel trains, maintaining air quality for passengers and preventing damage to the walls inside.
Being unable to access the land surrounding the site on the ground, as part of a £150,000 Great North Rail Project investment, Network Rail looked to the skies to solve the problem. A specialist helicopter team transported five tonnes of bricks and materials to build a new 2.6m diameter metallic grille on top of the shafts.