Sir Nigel Gresley is a preserved LNER Class A4 Pacific locomotive, named after the railway engineer who designed the streamlined class in the 1930s, and it remains a favourite at heritage railways and mainline railtours. This particular whistle clip comes from Trainz 2006, the railway simulator where the locomotive appears as a drivable engine, and it has since circulated among train enthusiasts who want an authentic British steam whistle for edits, presentations and model railway videos without recording a real locomotive themselves.