 As well as their iconic double Fairlies, the Ffestiniog railway also has a single Fairlie loco, the power bogie of which is essentially the same as those used by their double Fairlies.In both the UK and the USA, single Fairlies were the first locomotives in each country to use the European Walschaerts valve gear.The Stephenson link gear, which was usual at the time, used multiple eccentrics between the frames but the Walschaerts gear was mounted "outboard" of the frames and connecting rods.