I know they do it for a road crossing. Are there any other places they do it on a regular basis? A train near me blows their horn and I don’t think they are near a road crossing . There are 2 road bridges over the tracks very close by.
2 blasts when starting to move forward, 3 when reversing, repeated short blasts when entering or passing through a work area, or as needed with hazards on the track. 2 long, 1 short, 1 long when approaching a grade crossing, repeated as needed.
Excellent to know, there are freights in the city and around it here (Chicago) and they are at least 10 miles away from me, and I still hear them. Now I can visualize what they are doing (I lead a boring life)
To expand on that, here’s a wiki link with even more.
I just moved to Chicago… we have it lucky here! Where I moved from, the whole town was less than 0.5 miles from end to end and trains – multiple a day – run through the whole night. It’s 3am, BLAAAAAAAAAAAAAAAAAAAAAAAAR HOOOOOOOOOOOOOONK.
In Chicago the train noise is diffuse and drowned out… mostly by the shootings 
Note that they don’t sound horns at all crossings. “Quiet zones” can be established.
Older article :
http://www.wxow.com/story/17105493/new-quiet-zone-compromise
Brian
Most of Chicagoland is a Quiet Zone, so you don’t hear as many whistles for grade crossings as might otherwise be required (thank goodness).
I live near the South Loop railyards and stations, and most of what I hear seems to be informal warnings (quick short blasts) to workers roaming in the yards. One of the Amtrak guys sounds off across the river around 4 every morning. I think it’s pretty rare nowadays for anyone to know the whistle codes of yesteryear, much less use them. The engineers have a button that automagically sounds — — . — for grade crossings.
I have no citations, only experience. It is my personal belief that engineers will not be reprimanded for acknowledging the classic “kid waving at a train” with a short toot.
P.S. Returning a wave is almost mandatory unless the weather is crappy or the cab is buttoned up.
One of my hobbies is railroad photography. Usually I go track side far away from civilization. The engineers are almost universally very friendly. At a minimum, when the engine passes we get some horn blasts, bell ringing, and lights flashing. Plus a hand waving out the window. It’s a little thing that I always find sort of thrilling.
When my blonde wife is standing nearby, we get double the above attention.
Once while railfanning I had a switch list tossed out and another time a half-pint container of cool water (we must have looked thirsty).
That’s just way too cool. Lucky dog.
Once in Flagstaff, two other guys and myself got mooned! :eek: Have the photo to prove it. 
BNSF unit.
The very instant I get to sleep.
They have quiet hours here. The horn is muffled somehow.
In my area beside the tracks there are concrete pedestals painted white with a black “W” on them, I believe they indicate that the train should blow the horn at that point.
Correct. Those let the engineer know there is a crossing ahead. Some railroads use a W, some use an X.
The Argosy Casino in Kansas City (actually Riverside) had a road rebuilt to remove an at-grade crossing just outside a switching yard. Their hotel guests apparently didn’t like the horns blowing all night long less than a mile from their rooms. I don’t know if the casino paid for the whole thing or what.
It’s really complicated.
When do trains in US blow their whistles/horns?
Whenever they’ve done something they are proud of.
mmm
Wait a minute - does this mean US trains always give one long horn signal when they have stoppend before an adverse signal, and two long horn signals when the signal has changed and they proceed? The trains I commute with (in SW Germany) stop before a signal (between stations) almost every day at some point (busy lines), and trackside residents would raise hell if trains gave horn signals every time. Are US trackside residents that tolerant?