Most of us pass by the Clifton Rocks Railway without even knowing it is there. Constructed with great difficulty inside the cliffs of the Avon Gorge in order to reduce its visual impact on the picturesque surroundings, this funicular railway operated for 40 years against diminishing trade. Its closure before WWII did not mark the end of its useful life as it became a secret transmission base for the BBC.
Behind the entrance is a tunnel cut through the rock which extends at a steep angle to emerge in the now derelict small triangle of ground between the junction of Princes Lane and Sion Hill, adjacent to the Avon Gorge Hotel. Within this triangle of ground is the upper Station which has long since fallen into a state of disrepair. The tunnel itself forms a straight and direct connection between the upper and lower stations. A Description Of The Original Railway. The tunnel is 500 feet long, semi elliptical in cross section with a roof height of 18 feet and a width of 27 feet 6 inches it climbs a vertical distance of 240 feet on a rising gradient of about 1:2.2, that is a vertical rise of 1 foot for every 2.2 feet of forward travel. The tunnel was blasted and cut through badly faulted limestone and was brick lined in almost its entirety with a wall thickness of 2 feet.