Train whistles are used as a safety warning and also by the engineer to communicate to other railroad workers. It is also a nickname for an air horn on a diesel locomotive. Steam engine whistles were historically known as chimes in the US during the 19th century.
Whistle post is an advance warning to the engineer of an upcoming grade crossing. It is the point at which the engineer should begin sounding the whistle or horn.
I don’t have any actual W #RailArt pictures that I’ve found, but I did have some fun colorful ones from today’s #LumberTrain