the british rail class 40 is a type of british railway diesel locomotive. built by english electric between 1958 and 1962, and eventually numbering 200, they were for a time the pride of the british rail early diesel fleet. despite their initial success, by the time the last examples were entering service they were already being replaced on some top-link duties by more powerful locomotives. as they were slowly relegated from express passenger uses, the type found work on secondary passenger and freight services where they worked for many years, the final locomotives being retired from regular service in 1985.