The incredible work to repair one of UK's deepest railway ventilation shafts at Cowburn tunnel

Video report by ITV Granada's Paul Crone

In the heart of the Peak District, deep underground lies one of Britain's deepest railway ventilation shafts.

It leads to the famous Cowburn railway tunnel near Chapel-en-le-Frith, where dozens of passenger and feight trains pass daily.

Building the shaft back in 1888 was a feat of engineering and its been quite a job for the team to repair it today Credit: ITV Granada

But over time water damage has threatened the tunnel's ability to carry trains through it, meaning drastic action has had to be taken to fix the problem.

There's only one way to get to the problems via a custom built platform.

A custom-built platform is the only way to access the ventilation shaft Credit: ITV Granada

The shaft is 836 ft deep. That's considerably taller even that Blackpool Tower which is a mere 518 ft.

The shaft is 836 ft deep underground Credit: ITV Granada

For months, Network Rail have undertaken vital repairs on the shaft and drainage system which were built back in 1888.

Reporter Paul Crone went down the shaft to witness the team as they undertook the vital repairs

"Basically all I can describe it is like being in a shower, but heavier. Obviously we had to have proper suits on, dry suits." explains Jimmy Lunney from Network Rail.

Taking inspiration from the past, Network Rail crews have worked in tricky conditions to right the wrongs which have emerged over the last 127 years.

The work means trains can continue to run through Cowburn Tunnel for years to come.