This article is about the powered wheels on locomotives. For powered wheels on automobiles, see drive wheel. For steering control on automobiles known as that in the UK, see Steering wheel.
^Fowler, George L. (1909). Locomotive Dictionary (1909 ed.). New York: The Railroad Age Gazette. p. 37 – via Google Books.
^Forney, Matthias N. (1879). Catechism of the Locomotive. New York: The Railroad Gazette. p. 177 – via Google Books.
^Rattan, S.S. (2006) [1993]. Theory of Machines (second ed.). New Delhi, India: The McGraw-Hill Publishing Company Ltd. p. 560. ISBN0-07-059120-2 – via Google Books.