Since a conventional steam locomotive is directly driven, one of the few ways to ' gear' a locomotive for a particular performance goal is to size the driving wheels appropriately. One of six 6 ft 8 in (2.03 m) driving wheels belonging to 60163 Tornadoĭriving wheels are generally larger than leading or trailing wheels. On an articulated locomotive or a duplex locomotive, driving wheels are grouped into sets which are linked together within the set. in the Swiss Crocodile locomotive ) but their use is now confined to shunting locomotives. Jackshaft drive and coupling rods were used in the past (e.g. Coupling rods are not usually used, and it is quite common for each axle to have its own motor. On diesel and electric locomotives, the driving wheels may be directly driven by the traction motors. On a conventional, non-articulated locomotive, the driving wheels are all coupled together with side rods (also known as coupling rods) normally one pair is directly driven by the main rod (or connecting rod) which is connected to the end of the piston rod power is transmitted to the others through the side rods. On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive).
