When Totley Tunnel was built it was under land largely owned by the Duke of Rutland. He stipulated that there should be nothing left above the surface on his land, and if there had to be any work it hadn't to be in the grouse shooting season. The old 6th Duke died during the construction phase and the central airshaft was very definitely on his land and left a large imprint. The nothing left behind was this; https://www.flickr.com/photos/kazzle101/41169947300/ After 5 years of digging it was well behind schedule so they were probably glad to see the end of the job. When the headings from Totley and Padley met they were only 4 inches out of alignment.
From the road at ground level it looks like a beached submarine with conning tower, and it does from the air, too. The tunnel is offset to the side to prevent anything dropping on trains. The lining of the shaft is at least 18 inches thick and it was supported by the brick lined arched cavern below. A story circulates that they found a natural cave at that point, possibly. Varied rock conditions were found and some of the brickwork in the lining is 3 feet thick. There were a lot of underground pockets of water, but the cavern was helpful when construction was underway as 60 foot lengths of rail could be turned there. It's very wet.
This is a record of a totally unauthorised, and unsafe, visit underground to find the cavern; https://testchamber.net/drain-or-train-running-the-totley-tube/
Crazy fools!