A Majestic Mountain Top Adventure

Technical info

The Rack and Pinion System

The rack and pinion system used is that patented by the Swiss engineer Dr Roman Abt. The railway uses 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 railway, laid to a gauge of 2ft 7 ½ in (800 mm) which is common to most mountain railways, consists of a single track with 3 passing loops spaced equidistantly between Llanberis and the Summit. (Hebron at 1069 ft (326 m), Halfway at 1641 ft (500 m) and Clogwyn at 2556 ft (779 m)). The average speed of the trains is 5 mph (8 kph).

The Gradient

The total length of the railway is 4 miles 1188 yards (7.53 km), with an average gradient of 1 in 7.86. The steepest gradient on the route is 1 in 5.5. The gradients on the route make it unsuitable for a normal adhesion railway, so a rack and pinion system was installed. Snowdon Mountain Railway is the only public rack and pinion railway in the British Isles.

Steam locomotives

The company currently operates 4 coal-fired steam locomotives manufactured by the Swiss Locomotive & Manufacturing Co. of Winterhur. Three of which are the original ones dating from 1895 and 1896, whilst the remaining one was built in 1922. The first of the original locomotives cost £1525.

The boilers are inclined on the locomotives to ensure that the boiler tubes and the firebox remain submerged when on the gradient, a standard practice on mountain railways. The locomotive always runs chimney first up the mountain pushing a single carriage in front of it. For safety reasons the carriage is not coupled to the locomotive.

 No  Pic  Name  Works No  Date  Status
 2 Loco 2 at the Summit  Enid  924  1895  In service
 3 Loco 3 Approaching Summit  Wyddfa  925  1895  In service
 4 loco number 4 at Summit  Snowdon  988  1896  Out of service for remedial work
 5 Early No. 5  Moel Siabod  989  1896  Out of service
 6 Early Pic No. 6  Padarn  2838  1922  In service
 7 Loco 7  Ralph  2869  1923  Out of service
 8 Locomotive 8  Eryri  2870  1923  Out of service

Diesel locomotives

Between 1986 and 1992 the company took delivery of 4 British built diesel locomotives to complement the steam fleet at a cost of £250,000 each. These locomotives are powered by 320 Horsepower (238 kW) six cylinder turbocharged Rolls Royce diesel engines of 12 litres capacity. Manufactured by Hunslet Engine Co. Leeds.

 No  Pic
 Works No  Date  Status
 9 Number 9 at Clogwyn  Ninian  9249  1986  Re-engined 2011
 10 Number 10 Diesel at Rocky  Yeti  9250  1986  Re-engined 2011
 11 Numer 11 Diesel Approaching  Peris  9305  1991  Re-engined 2012
 12 Loco 12  George  9312  1992  Re-engined 2012


The original carriages were open above the waist and had canvas curtains, which provided little protection against the elements. Between 1951 and 1957 the superstructure of the original carriages was modified to produce the enclosed bodies. Each of these carriages had a capacity of 56 passengers, plus a guard. Every passenger carriage had its own set of pinions, with automatic brakes as an added precaution. If the train's speed exceeded 7.5 mph for any reason, the brake came on.

In 2012 the first of 4 new carriages was delivered to Snowdon Mountain Railway with the remaining 3 due for delivery early in 2013. These new coaches have been designed and built in the UK by a partnership between Garmendale Engineering Limited of Ilkeston, Derbyshire and the Hunslet Engine Company, to a performance specification defined and project managed by the Railway.

Not only do the carriages boast higher levels of passenger safety, space and comfort, but the manufacturing process is a world first in the rail industry. Although the material chosen for the carriage body had been used in the production of road freight vehicles in the recent past, it has never been used in the production of rail vehicles.

Combining strength and thermal insulation characteristics with extremely low weight made the choice of this material particularly appropriate for our carriage project. The new carriages also have a stunning new livery which will be reflected on the diesel locomotives that will power them up the mountain. Also this choice has allowed the Railway to increase the capacity of each carriage from the current 56 to the new capacity of 74 without change in seating space from previous carriages. In addition to this higher carrying capacity all four carriages will now have wheelchair access therefore allowing more users the opportunity to travel every day.

The carriage bogies have been designed and built by Hunslet Engine Company at the home of their parent company LH Group in Barton under Needwood. Rather than a revolutionary design, the bogies represent an incremental improvement to an existing design that has been in passenger service since 1986 and latterly improved in 2006 on the old carriage number 10 and the summit project flatbed truck. In this way Hunslet have built on a solid safety record but improved the performance of this safety critical piece of equipment. The original carriages will now be taken out of service with some of them going to have new bodies constructed on them for our new Heritage Steam Experience which is due to start in June 2013.

Manufacturer: Lancaster Carriage & Wagon Co. Ltd

 No  Date  Status
 1  1895  Re-bodied for permanent way engineering vehicle
 2  1895  In service Snowdon Lily re-bodied 2013
 3  1895  Out of service
 4  1895  Out of service
 5  1895  Out of service
 8  1895  Out of service

Manufacturer: Schweizerische Industrie-Gesellschaft, Neuhausen

 No  Date  Status
 6  1923  Out of service
 7  1923  Out of service

Manufacturer: East Lancashire Coach Builders Ltd

 No  Date  Status
10  1987  Re-engineered for summit service vehicle & rescue 2013

Manufacturer: Hunslet bogies and brakes, Garmendale chassis and bodies 2013

 No  Date  Status
 14  2013  In service
 15  2013  In service
 16  2013  In service
 17  2013  In service

Caboose Car

Manufacturer: Rebuilt from 1895 Lancaster Carriage & Wagon Co. Ltd carriage frame.

Traffic control

A Traffic Controller at Llanberis, who is responsible for the overall movement of traffic, controls the movement of trains. Communication between Llanberis, the Summit and Clogwyn, as well as the guard of each train is by means of two-way radios.

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