Original: They were fitted with the Sulzer 12LDA28C  twin-bank twelve-cylinder unit producing  - though this was later derated to  to improve reliability - and have been used on both passenger and freight trains on Britain's railways for over 40 years.
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 Britain's railways for over 40 years.