Original: In the early 1970s, fifty were fitted with electric train supply in place of their steam heating boilers and assigned to work services on the Midland Main Line from London St Pancras to Nottingham, Derby and Sheffield.
Simplified: In the early 1970s fifty were fitted with electric train supply in place of their steam heating boilers, and assigned to work services on the Midland Main Line from London St Pancras to Nottingham, Derby and Sheffield.