Whistle post

A whistle post is like a big whistle that trains use to make a sound when they are approaching a certain area on the tracks.

It's important for the train to make this sound so that people and animals nearby can hear it coming and move out of the way.

The whistle post is usually a tall pole with a whistle attached at the top. As the train gets closer, the conductor will pull a lever that blows air through the whistle, creating a loud noise.

So, when you hear the whistle sound, it means a train is coming and you should be careful and stay away from the tracks.