École Nationale Supérieure de
Techniques Avancées

Résumé

In the field of railway systems, I worked on two important and undesirable noises : the squealing noise and the flanging noise. A squealing noise, the one on which I focused, is a high-pitched sound that is produced by the friction between the wheel and the rail, whereas the flanging noise is due to the contact between the wheel flange and the side of the rail. To detect a squealing noise, I was provided some train passing-by recordings. The goal was first to analyze them and find some relevant clues of squealing noises. Then, I had to build a program that automatically detects the presence of this kind of noise and report it to the user. It can be mainly identified by the doppler effect it generates, its strong sound intensity level, its typical frequency and its position regarding the wheel axle. However, it is always hard to find, because of many background and rolling noises. In the end, over more than 80 recordings I worked on, only 10 contained an obvious clue of squealing noise, which my program managed to find.