- Wheel arrangement
Locomotive wheel arrangement is how the wheels of the locomotive are arranged by type, position, and connections. There are several notations used to describe wheel arrangements, depending on the country; also, a same country will typically use a different scheme for
steam locomotive s on the one hand, and electric and diesel locomotives on the other hand.In the
United States , theUnited Kingdom andIreland , theWhyte notation is generally used forsteam locomotive s. British practice uses a slightly simplified form of the UIC notation for diesels and electrics. The United States uses theAAR wheel arrangement scheme for diesels and electrics.In mainland
Europe , theUIC classification scheme is generally used, with some exceptions. InFrance , theUIC classification is used for diesels and electrics while a scheme similar to theWhyte notation , but counting axles insteads of wheels, is used for steam locomotives.Especially in steam days, wheel arrangement was an important attribute of a locomotive, because there were many different ones, each optimised for a different use. Modern diesel and electric locomotives are much more uniform, usually with all axles driven.
Major Notation Schemes
*
AAR wheel arrangement - Used largely throughout the US and Canada.
*UIC classification - Used for diesel and electric locomotives in the UK. Used in mainland Europe for all locomotive types, including steam.
*Whyte notation - Used for shunting locomotives and steam locomotives in the UK.
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