May I interject on this topic?
As regards decibels, it is generally a measurement where the intensity of the noise varies over a given period of time, such as a day. And there will be an average level. That is often what happens—and this is the most bothersome noise for people—when impulse noise occurs. We have heard examples of this throughout Canada when, for example, railway companies are switching rail cars in the yard in the middle of the night. When the car is unhooked and it bumped into another, if the shock absorber at the other end has not been improved, impulse noise occurs, and that is a nuisance.
Now, when you measure noise over the course of the day, the decibel level may seem somewhat reasonable, but we see that there is nevertheless a nuisance. That is the kind of situation that can be eliminated thanks to better technology and better schedule management, mechanisms, motors, equipment, and locomotives.