In the early 1960s, the British Transport Commission (BTC) planned to remove steam locomotives from the British Rail network by 1968. This would require many new locomotives to replace existing steam engines, the first being the Class 46. During the building of these, it was realised that a larger number of locomotives would be required. The final 20 contracted Class 46 locomotives we cancelled and a new tender was put out.
The first twenty locomotives were fitted with Westinghouse brakes, with the remainder built with Metcalfe-Oerlikon brake systems. Based on the success of the prototype another order of 270 locomotives was made, revised upwards to the final total of 512. 310 of these were built at Brush in Loughborough, with the remainder built by the BR Crewe Works. The new tender was given to Brush with the requisite of the parts from the cancelled Class 46 to be used and the Class 47 was born.
The Class 47's were used across the whole British Rail network, in both passenger and freight roles. Most 47s were built with steam heating which was later replaced with electric. Eighty-one were built for freight-only duties with no heating and were fitted with slow speed control while twenty-two had dual or just electric heating and were used for passenger, parcels, and mail trains.