The British Rail Class 37 is a diesel-electric locomotive. Also known as the English Electric Type 3, the Class was ordered as part of the British Rail modernisation plan. The Class 37 became a familiar sight on many parts of the British Rail network, in particular forming the main motive power for Inter-City services in East Anglia and within Scotland. They also performed well on secondary and inter-regional services for many years. The Class 37s are known to some railway enthusiasts as “Tractors”,2 a nickname due to the agricultural sound of the diesel engine of the locomotive.