This cache is placed in a cutting between the Sherwood Rise Tunnel and New Basford Station on the old Great Central Line. Access is Via Haydn Road / Camelot Avenue, and there is space to park there too.
The northern portal of the tunnel is stil visible at the south of the cutting in among the trees for those with a brave heart and a tolerence for detritus. The background image shows the tunnel back in it's day.
http://youtu.be/9uaKAL2iQCw This video shows trains using this cutting. The opening shot is the bridge over Haydn Road.
In 1897 the Great Central Railway itself was formed, becoming the last steam mainline in the United Kingdom. Two years later in 1899 "The London Extension" was officially opened to passenger and freight traffic, allowing more direct journeys from the capital to Nottingham, Leicester, Sheffield and Manchester.
In 1966 the line closed as a though route to London and the line was severed just south of Rugby while the proud station at Nottingham Victoria was demolished.
http://en.wikipedia.org/wiki/Great_Central_Railway
P.S. It can get muddy underfoot here, so use your skill & judgement :-)