Engineer 's notes Derbysulzers.com - Retrieved on NUMBER@1 They were part of the British Rail Class NUMBER@2 order , but differed from their classmates by being fitted with a ORGANIZATION@1 NUMBER@3 12LVA24 power unit producing , as opposed to the standard 12LDA28C twin-bank twelve-cylinder unit of the remaining fleet .

They were part of the British Rail Class NUMBER@2 order , but differed from their classmates by being fitted with a ORGANIZATION@1 NUMBER@3 12LVA24 power unit producing , as opposed to the standard 12LDA28C twin-bank twelve-cylinder unit of the remaining fleet .
