Because the single driving axle was behind the firebox, Crampton locomotives usually had outside cylinders. However, some inside cylinder versions were built using indirect drive, then known as a
jackshaft. The inside cylinders drove a
crankshaft located in front of the firebox and the crankshaft was connected to the driving wheels by outside rods. Some long-wheelbase s were also built using this crankshaft system. The boiler feed-pump was often driven from the crankshaft as well because many Cramptons were built before the
injector was invented. Another feature on some Crampton locomotives was the use of a boiler of oval cross-section, to lower the centre of gravity. It was later seen as a major flaw, because the internal pressure would tend to push the boiler into a circular cross-section and increase the risk of
fatigue. ==Usage==