driving axle

plural driving axles · alternative drive axle

1. An axle which transfers power to a powered wheel from an engine, as in a steam locomotive.

   And what about the cracked driving axles that took a number of the Southern "Merchant Navy" Pacifics out of action and brought various borrowed strangers on to Southern metals, such as V2 2-6-2s from the Eastern Region?

   1961 March, Cecil J. Allen, “Locomotive Running Past and Present”, in Trains Illustrated, page 154