Milford Tunnel in Derbyshire is a twin track railway tunnel on the Midland Main Line which runs under a hill called the Chevin between Duffield and Belper. It was built in 1840 by the Stephensons for the North Midland Railway.
When finished, it was 855 yards (782 m)  long.
The west side of the Derwent valley has a number of gritstone outcrops, one being Burley Hill to the south of Duffield, another being Castle Hill in Duffield itself. The valley here however was too narrow, and already occupied by the village of Milford from which the tunnel gets its name, and one of Jedediah Strutt's cotton mills.
The name Chevin has Celtic origins, but the hill is often called Firestone Hill, for the spot on which the beacon fires were lighted to rouse the country when peril of invasion or other dangers were imminent.
For some reason the North Midland built very ornate portals at the northern ends of their tunnels, in this case a Saxon-inspired arch, while the southern ends were relatively plain. The north portal was originally set into a surrounding area of random stonework, which has become totally overgrown. It is expected that the effect of trimming back the vegetation as part of the electrification project will have the effect of restoring it to its former appearance. Both portals are grade 2 listed, being part of the Derwent Valley World Heritage site.
At the summit of the hill there was built a substantial tower, which still exists, the purpose of which has been a matter for speculation. It has generally been thought that it was to check the alignment of the tunnel construction, and was equipped with a rotating telescope. It has been pointed out that such a facility appeared with no other tunnel of the time and there is an alternative theory that it was concerned with supervising the passage of trains through the tunnel. In effect an early experiment with a form of block working, instead of the time interval system commonly used.
When the Midland Railway upgraded the line to four tracks south of the tunnel, a signal box was installed to control the junction of the goods and passenger lines, also providing warning distant signals at the north entrance.
- Pixton, B., (2000) North Midland: Portrait of a Famous Route, Cheltenham: Runpast Publishing
- Naylor,P. (Ed) (2000) An Illustrated History of Belper and its Environs Belper: M.G.Morris
- Jacobs, G., (Ed) (2005 2Rev) Midlands and North West: Bk.4 (Railway Track Diagrams) Bradford on Avon:TRACKmaps.
- Alan Baxter and Associates in World Heritage News, Issue 14, 2014, Derwent Valley Mills Partnership
- Huson, S., (2009) Derbyshire in the age of steam, Newbury: Countryside Books
- for Milford Tunnel