Snowdon Mountain Railway is the only public rack and pinion railway in the British Isles.
Snowdon Mountain Railway was constructed between December 1894 and February 1896 at a total cost of £76,000, from the base station at Llanberis at a height of 353 ft (107.6m) above sea level, to the Summit Station at 3493 ft (1065m). The summit of Snowdon at 3560 ft (1085m) is the highest peak in England and Wales.
The railway uses rack and pinion system with double rack rails, fastened to steel sleepers between the running rails. Each locomotive is equipped with toothed pinions (cogwheels), which engage the rack and provide all the traction necessary to scale the steepest inclines. On the way down, the rack and pinion system also acts as a brake. The gauge is 2' 7.5" s, and the line is a single track with 3 passing loops. The length is 7.53km with the steepest gradient of 1 in 5.5.
There are currently operates 4 coal-fired steam locomotives manufactured by the Swiss Locomotive & Manufacturing Co. of Winterhur. There have been three others which are not currently used. There are 4 diesel loco's from the late 1980s early 1990's. There are also three railcars, which can run coupled together. There are 8 carriages available for use.