There are many times when a tunnel needs a leak sealing, preventing water ingress and enabling it to continue being used for road, rail, foot, or cycle traffic. But the task may be a somewhat larger one if the tunnel has been derelict and closed for many years.
Such could be the case for the Rhondda Tunnel, which was closed in the 1968 Beeching cuts and has been sealed up at both ends since 1981.
However, as the Daily Express has reported, the Rhondda Tunnel Society has submitted a planning application to Rhondda Tynon Caf Council to reopen the line as a walking and cycling tunnel. At 3.1 km, it would be the longest tunnel of this kind in Europe and the aim of the society is to turn it into a major tourist attraction that would boost the local economy.
The project would cost £13 million with substantial construction and remediation work. That may include some leak sealing and other structural work as well as clearing debris out of the tunnel, surfacing work and the provision of bike hire and visitor centre services at either end of the tunnel.
A public consultation has now begun on the proposals, with the planning application going in last month.
The project may be the largest of its kind, but it will certainly not be the first. Other former railway lines brought back into use for walkers and cyclists include the Monsal Trail in Derbyshire, which has six tunnels. However, even the longest of these are only around 400 metres from end to end.
With some other lines closed in the Beeching cuts being fully restored for passenger services, there may be many more tunnels that have been (or need to be) given substantial maintenance, including the sealing of leaks as they take on a new lease of life.