There is an information board nearby, by the Derbyshire Archaelogical Society, which describes the history of the tunnel and there is also an old wagon mounted on both plateway and railway.
[From Wikipedia. Read more here https://en.wikipedia.org/wiki/Fritchley_Tunnel ]
Butterley Gangroad linked Hilt's Quarry and other limestone quarries at Crich with the Cromford Canal at Bullbridge. The first railway project of Derbyshire civil engineer Benjamin Outram (1764–1805), the line was originally a horse-drawn and gravity-driven plateway, a form of tramway that Outram popularised. The line was constructed in 1793, with the tunnel being required to go under a road junction in Fritchley. In the 1840s, upgrading took place to accommodate steam locomotives, and part of the original line was moved. The southern part of the tunnel was rebuilt with an entrance slightly to the west of the original one. The tunnel's walls bear evidence of these changes. The railway remained in use until 1933