The tunnel is aligned approximately north-south and is on a left-hand curve and a falling gradient when travelling in the down direction.
[5] This is one of five tunnels on the Cornwall Railway, all of which are lined with masonry and topped by brickwork at the crown of the arch.
[5] This tunnel passes through 216 feet (66 m) of hard greenstone which the builders were able to drill and blast through using nine tons of powder (because dynamite had not yet been invented).
[5] On 7 November 1903, the architect Silvanus Trevail committed suicide in the toilet of a train in the tunnel.
[7][8] The name "Brownqueen", which applies to both the tunnel and the forest around it, is a modern corruption of the old Cornish term "Brow Gwyn", meaning "white mound".