Absolutely NOT The "Hogwarts Express"

   Class 37 409 (Loch Awe) on the Glenfinnan Viaduct.

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 theBritish Rail network, in particular forming the main motive power for InterCity services in East Anglia and within Scotland. They also performed well on secondary and inter-regional services for many years. Many are still in use today on freight, maintenance, and empty stock movement duties.