The Treamble branch is always quoted as closing in 1956 'last revenue-earning traffic 1949'. The reason for this unusual terminology is that the branch was used for the storage of wagons after 1949. Some are visible on one of the website pictures. See below.
My understanding is that the Gravel Hill extension was laid in 1888, but without parliamentary sanction (new railways required an act of parliament). Perhaps the Cornwall Mineral Railway was just chancing it. Records seem to agree that Gravel Hill mine was abandoned in 1882, so was the railway a wild-west style attempt to revive the mine?
The OS 25 inch map for 1906 shows not the slightest trace of any railway to Gravel Hill. My guess is that the tracks lasted for no more than a year or two. It needs to be borne in mind that OS maps were not revised systematically - hence something which caught the surveyor's eye in one year, may be gone in the next.
Many thanks Roy
Gareth Thornton Andrew Triggs & Roger Winnen
All the best Gareth Many thanks to you Gareth