The braking system also uses the rack to slow and stop the trains with the brakes fitted to the pinion axles on the locomotives and carriages.Snowdon is unique in rack railways by having a derailment protection device fitted either side of the rack which engages with fittings under each carriage and locomotive which ensures that the vehicle cannot lift out of the rack.Between 19 the company took delivery of 4 British built diesel locomotives to complement the steam fleet at a cost of £250,000 each. The original carriages were open above the waist and had canvas curtains, which provided little protection against the elements.
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.
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.
Most railways use simple adhesion of rail wheels on the rails to move a train along a track.
In the case of mountain railways the gradient of the track means that simple adhesion does not work.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 Snowdon track was designed in Switzerland in 1895 meaning that the track and rolling stock are metric.The track gauge is 800mm or 2ft 71/2 inches between the rails.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.