Toadmoor Tunnel

[1] 128 yards long, it was cut through an unstable hillside on a notoriously difficult line of route.

What had initially been expected to be acceptably strong coal-bearing rock turned out to be wet shale.

On beginning excavation a landslide occurred, the effects of which can still be seen further up the bank in Thatcher's Wood.

[2] The engineer Frederick Swanwick decided to proceed using the cut-and- cover method, with stone retaining walls and invert, and a brick-built masonry arch over the top, which gives it its unusual elliptical shape.

[3] Other problems arise with a need for increased line speed and the arrival of electrification, not least because it is grade 2 listed and part of the Derwent Valley World Heritage Site.