What is the high pitched noise you hear on the tracks before a train comes?



Sitting at a train station and was alway curious what caused that high pitched tsssss you hear from the tracks before the train comes into sight.

In: Physics

That is the sound of the train rolling on the rails transferred along the rail. The vibration of the rail will move the air around the track and that is the sound you hear.

That is caused by the train rolling on it and the bending of the track because of the weight of the train.

Sound travels faster in solids and can reach a lot further than in air.

Fun fact if anyone is interested-
When the train is out in idle and going down heel it’s practically silent so you can’t hear it coming. Don’t jog on train tracks!