The British Rail Class 46 is a class of diesel locomotive. They were built from 1961 to 1963 at British Railways' Derby Works and were initially numbered D138–D193. With the arrival of TOPS they were renumbered to Class 46. Along with the similar Class 44 and 45 locomotives, they became known as Peaks.

Fifty-six locomotives were built. The first was withdrawn in 1977 and all were withdrawn by the end of 1984. All surviving examples now preserved.