Network Rail has completed essential maintenance to Cowburn Tunnel on the Hope Valley line as part of a major £800,000 Great North Rail Project investment.
The tunnel, between Edale and Chinley, goes underneath key peaks near Kinder Scout and Mam Tor in the Peak District National Park.
Because of its remote location, helicopter pilots were drafted in to transport vital materials and components for work on the tunnel’s ventilation shaft. Vertically dug 241 metres into the hillside, it’s one of the deepest railway ventilation shafts in the country. If it were a building it would be taller than Canary Wharf in London.
But for nearly 130 years, as well as providing air to the tunnel more than 250 metres below, the ventilation shaft has also inadvertently acted like a huge drainpipe. When rain falls on the land above, it seeps through the soil before making its way through the ventilation shaft’s brickwork, cascading like a massive shower head into the tunnel and tracks below.
To solve this Network Rail engineers has installed a sophisticated system of drainage pipes to collect the water in a controlled way so it can be diverted into drains in the tunnel itself.
Dennis McGonnell, Network Rail works delivery manager, said: “It’s a huge privilege to keep heritage structures like Cowburn Tunnel in good condition for rail passengers and freight and it’s amazing to see up close the quality of the Victorians’ workmanship.
For the new pipes and water collecting devices to be installed, engineers built a temporary lift platform to work from using winches and pulleys. Network Rail teams were lowered into the ventilation shaft in a custom-built cradle, similar to their Victorian predecessors who excavated the shaft 127 years before them. Doing the work this way meant trains could still run in the tunnel below without disrupting passenger or freight services. Drainage improvements at track level could only take place on Saturday nights when trains weren't running.