0-4-0
LOCOMOTIVE WHEEL ARRANGEMENT
Four-coupled; 0-4-0T; 0-4-0ST; 0-4-0WT; 0-4-0DH
Under the Whyte notation for the classification of steam locomotives, represents one of the simplest possible types, that with two axles and four coupled wheels, all of which are driven. The wheels on the earliest four-coupled locomotives were connected by a single gear wheel, but from 1825 the wheels were usually connected with coupling rods to form a single driven set.