[2] The tunnel was engineered underneath Colborne, part of a 1,700-foot (518 m) moorland between Kinder Scout and Rushup Edge.

[7] Although the workings were relatively dry for tunnel builders at the time, on one occasion the headings filled with water to a depth of 90 ft (27.4 m).

[citation needed] Repairs to the ventilation shaft were carried out in August to September 2021 by Network Rail, with an investment of around £800,000.

The work involved installation of a system of drainage pipes inside the shaft to collect rainwater which seeps through its brickwork from the soil, which had been cascading onto the railway below.

To avoid disrupting rail traffic, helicopters were used to airlift equipment to build a temporary platform to lower engineers inside the shaft similarly to the original constructors.