People learned how to whistle ever since they thought up the idea of putting their lips together and blowing. But when did trains learn to whistle? Believe it or not, someone had to invent the steam whistle, and it came after steam trains were in regular operation. The man known for inventing this whistle was Adrian Stephens, who was chief engineer at the Dowlais Ironworks in Merthyr Tydfil, Wales. The purpose of his 1833 invention was to warn of low water levels in a steam boiler, by having ste