The Snowdon Mountain Railway (SMR) is a narrow gauge rack and pinion mountain railway in Gwynedd, north-west Wales. It is a tourist railway that travels for 4.7 miles (7.6 km) from Llanberis to the summit of Snowdon, the highest peak in England and Wales.The SMR is the only public rack and pinion railway in the United Kingdom, and after more than 100 years of operation it remains a popular tourist attraction. The line is owned and operated by Heritage Great Britain plc, operators of several other tourist attractions in the United Kingdom.
The railway is operated in some of the harshest weather conditions in Britain, with services curtailed from reaching the summit in bad weather and remaining closed during the winter from November to mid-March. Single carriage trains are pushed up the mountain by either steam locomotives or diesel locomotives. It has also previously used diesel railcars as multiple units.The SMR was the inspiration for the fictional Culdee Fell Railway, appearing in the story book "Mountain Engines", part of the "The Railway Series" written by the late Reverend W. Awdry. The Railway Series books were the basis for the popular Thomas the Tank Engine and Friends children's television series; as yet however the Culdee Fell Railway has not been included in the televised episodes (though the major characters do have toys based on them).
The Llanberis complex also houses the company offices, locomotive shed and workshop building. The forecourt has recently been changed from a visitor car park into a cafe/picnic area.
Traffic and train movements are controlled from Llanberis: communication between Llanberis, Clogwyn and the Summit, as well as to trains' guards, is by two-way radio.The line has three passing loops, around 15 minutes travelling time apart. Going up the mountain, these are at Hebron, Halfway and Clogwyn stations. The operation of the Hebron and Halfway loops was converted to semi-automatic operation in the early 1990s. The Clogwyn loop is still staffed and retains the original mechanical point levers. Waterfall station had a siding but never a loop, and has been closed for many years.
All three passing loop tracks are on the north-west side of the main running line - this is in general the "downhill" side, where the mountain slopes away from the line. This means that, if required, the line could be easily be converted to double track without the need to cut into the rock face to widen the formation.Including stops at the passing loops, the train takes an hour to climb to the summit and an hour to descend again, at an average Speed of around 5 mph (8.0 km/h).
Passenger trains normally run from Llanberis to the Summit. The wind speed is measured at Clogwyn Station and used to determine if trains can continue to the summit. Trains terminate at Rocky Valley Halt when the weather is too bad to allow them to proceed safely to the summit.It is possible for two trains to run together 'on sight', which involves the second train following shortly (more than two minutes but less than five) after the first, and keeping a safe distance throughout the journey. This is known as a 'Doubler'. All platforms and passing loops are long enough to accommodate two trains.
The two Llanberis platforms are dedicated, one for arrivals and the other for departures. Arriving trains empty of passengers then shunt to the other platform. At the Summit station arriving trains generally alternate between the two platforms.When steam and diesel trains run together, it is normal for the diesel to lead up the mountain. This allows the steam train to enter the departure platform and load at its leisure, while the diesel moves across from the arrival platform from a quick turn-around.Locomotives spend the whole day with the same carriage. Any locomotive can work with any carriage, although carriage No.10 (the most modern) usually runs with a diesel locomotive.