The carrying wheels on a steam locomotive are those wheels that are not driven, i.e. they are uncoupled and run freely, unlike coupled or driving wheels. They are also described as running wheels and their axle may be called a carrying axle. Carrying wheels are referred to as leading wheels if they are at the front, or trailing wheels if they are at the rear of the locomotive. See main article Bogie.
In particular reference to steam engines, the carrying wheels have a very important purpose of allowing the engine's weight distribution to be altered. For example in the use of leading wheels it would allow the boiler to located further forward of the driving wheels, the weight of which counters the leverage imposed by the drawbar and the load of the pulled wagons/cars about the fulcrum of the rearmost driving wheel. Similarly the trailing wheels can move the fulcrum to the rearmost trailing wheel. Such change can dramatically improve the operating speeds of engines and their tractive effort.
Famous quotes containing the words wheels and/or carrying:
“A cruel story runs on wheels, and every hand oils the wheels as they run.”
—Ouida [Marie Louise De La Ramée] (18391908)
“The sacrifice to Legba was completed; the Master of the Crossroads had taken the loas mysterious routes back to his native Guinea.
Meanwhile, the feast continued. The peasants were forgetting their misery: dance and alcohol numbed them, carrying away their shipwrecked conscience in the unreal and shady regions where the savage madness of the African gods lay waiting.”
—Jacques Roumain (19071945)