This cache is NOT above ground. You will need a good torch to find this cache.
Neidpath Tunnel is about 600m long and is easily walkable. To claim a find you will need to take a photo of yourself, including your face, inside the workers retreat that is carved into the side of the tunnel. It is obvious where this retreat is and the only one in the tunnel.
The tunnel was opened in 1864 and finally closed in 1954. It was used extensively in WW2 and is even rumoured to have housed the Royal Train overnight to protect it from bombs when the King visited Edinburgh. Some locals also say the tunnel is haunted