Original: A total of 512 Class 47s were built at Crewe Works and Brush's Falcon Works, Loughborough between 1962 and 1968, which made them the most numerous class of British mainline diesel locomotive.
Simplified: They were fitted with the Sulzer 12LDA28C twin-bank twelve-cylinder unit producing (later derated to 2580bhp to improve reliability), and have been used on both passenger and freight trains on Britains railways for over 40 years.