Snowdon Mountain Railway
Snowdon Mountain Railway, Llanberis, Gwynedd, LL55 4TY.
The Snowdon Mountain Railway is a narrow gauge rack and pinion mountain railway in Wales. It is a tourist railway that travels for 4.675 miles (7.524 km) to the summit of Snowdon, the highest peak in Wales.
It is the only public rack railway in the British Isles and after more than 100 years of service it remains a highly popular tourist attraction. It is operated by a mixture of steam locomotives, diesel locomotives, and diesel railcars. The line is owned and operated by Heritage Great Britain PLC.
The railway starts at the side of the main road in Llanberis and consists of a single track with passing loops between Llanberis and the summit. The loops are around 15 minutes travelling time apart. All three passing loops are on the north-west side of the line so that, if traffic was heavy, the line could easily be converted to double track.
The total length of the railway is 4 miles 1188 yards (7.524 km), with an average gradient of 1 in 7.86. The steepest gradient on the route is 1 in 5.5, and this occurs in a number of places.
1895-6 Five locomotives were built by the Swiss Locomotive Works, Winterthur, though only four of them were in service. They are of the 0-4-2 Abt type, with horizontal cylinders placed above the platform near the middle. The piston-rods at the front end of the cylinders actuate a heavy rocking lever, to which the outside connecting-rods are attached. Three more engines of similar type have since been built by the same firm, (1922- 3). 
Sources of Information
-  Wikipedia