The Snowdon Mountain Railway uses a rack and pinion system involving a single bar of steel with machined teeth cut into the edge, which was patented by the Swiss locomotive engineer Dr Roman Abt at Arau. The line runs between Llanberis (nprn 41454) and Snowdon Summit Station (nprn 32619) and it opened in 1896. The railway has a narrow gauge of 2 feet 7 ? inches (800 mm) gauge, and consists of a single track with three passing loops. It is approximately 7.53 kilometres long with an average gradient of 1 in 7.86.
Source: David Gwyn & Merfyn Williams, 'A Guide to the Industrial Archaeology of North West Wales', Association for Industrial Archaeology, 1996.
B.A.Malaws, RCAHMW, 13 November 2012.