Toadmoor Tunnel (originally called Hag Wood Tunnel) was built at

Ambergate Ambergate () is a village in Derbyshire, England, situated where the River Amber joins the River Derwent, Derbyshire, River Derwent. It is about south of Matlock, Derbyshire, Matlock. The village forms part of the Heage and Ambergate ward of ...

Derbyshire Derbyshire ( ) is a ceremonial county in the East Midlands of England. It borders Greater Manchester, West Yorkshire, and South Yorkshire to the north, Nottinghamshire to the east, Leicestershire to the south-east, Staffordshire to the south a ...

, England, as part of the

North Midland Railway The North Midland Railway was a railway line and Great Britain, British railway company, which opened a line from the city of Derby in Derbyshire to the city of Leeds in Yorkshire in 1840. At Derby, it connected with the Birmingham and Derby J ...

, which opened in 1840. 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.Alan Baxter and Associates in ''World Heritage News,'' Issue 14, 2014, Derwent Valley Mills Partnership 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. Because of this, it took 15 months to build, instead of the planned two. It is thought that a second landslip may have occurred sometime later, so that it was braced with steel hoops at its southern end. Because of the tunnel cross section the depth of ballast under the track is adequate in the centre but almost nothing close to the walls, which produces settlement in the middle and crushed ballast at the edges.Balfour Beatty: Polyurethane slab track 4 August 2014
/ref> Other problems arise with a need for increased line speed and the arrival of electrification, not least because it is

grade 2 listed In the United Kingdom, a listed building is a structure of particular architectural or historic interest deserving of special protection. Such buildings are placed on one of the four statutory lists maintained by Historic England in England, Hi ...

and part of the Derwent Valley

World Heritage Site World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...

External links

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"Picture the Past" Toadmoor Tunnel c.1957

References

{{coord, 53.06051, N, 1.48070, W, region:GB_source:enwiki-osgb36(SK349516), display=title Rail transport in Derbyshire Railway tunnels in England History of Derbyshire Tunnels in Derbyshire Tunnels completed in 1839