In a typical city, such as Great Toronto Area, How far generally u can hear a train whistle? what is the most diffifcult object/sound berrier for the horn to overcome? tall skyscrapes? modern highways?
If not speaking about too quiet place (such as some northern small towns in Canada), I found that the maximum distance to hear a whistle is about 4.2km(sorry we use KM here) and it’s a very quiet night in the quiet semi-rural Scarborough city of Toronto, the whistle is so faint that only a good pair of ears(as mine :P) can detect it. I wonder how it is possible for the whistle to be heard for 100KM in Alaska as reported in some science book, sure it is a place almost no human inhabitants and no background noise?
BTW, is the horn DB different from train to train? like some horn is loud and some are weak? isn’t there is a regulation about the DB level?
It is part of my analysis of physics courses to say how sound wave can be spreaded, so the more details the more appreciated.
THANK YOU.