Complex sentence: British Rail services to Moorgate were initially steam-operated before being converted to Cravens-built diesel multiple units and British Rail Class 31 locomotives class hauling non-corridor stock which remained in operation until the mid- 1970s.
Split into simpler sentences: British Rail services to Moorgate were initially steam-operated. Steam was replaced by Cravens-built diesel multiple units and British Rail Class 31 locomotives class hauling non-corridor stock which remained in operation until the mid- 1970s.