I have been researching the tunnel hidden beneath Mow Cop for a couple of years now and I think I have found all that there is to find. Including the tunnel!
Here is the article.
Underneath the unsuspecting village of Mow Cop, lies a tunnel that has been hidden for over around 120 years...
https://discover.hubpages.com/education/Mow-Cop-Tunnel-Tramway