The Great Northern Railway (GNR) No. 1 class Stirling Single is a class of steam locomotive designed for express passenger work. Designed by Patrick Stirling, they are characterised by a single pair of large (8' 1") driving wheels which led to the nickname "eight-footer". Originally the locomotive was designed to haul up to 26 passenger carriages at an average speed of 47 miles per hour (76 km/h)." They could reach speeds of up to 85 mph (137 km/h).