Horn blasts

I live near a crossing and am used to hearing the Long, long, short, long series of horn blasts. Recently, I noticed the conductor just layed on the horn with one consecutive long blast. Could this have been to warn someone on the track? I thought an emergency warning was a series of short blasts? Any idea why the long consecutive blast?

first it was Engineer blowing horn, second most likely a person or car was fouling crossing.

Sorry, so the ENGINEER controls the horn. Okay, now I know. Still, what about the long continuous blast v. series of short ones for an emergency? I'm fascinated by the code of what these sounds mean.

series of short blast is usually used for person or animals near right of way.
a long continuous blast , means I am about to obliterate whatever is in way.

Interesting. Is there a book/list of what means what?

listed in rules like Norac or GCOR under whistle signals.

One long and loud to blow out the eardrums of that punk kid playing chicken with me.

One consecutive long blast, I thought, was to signal station departure.

In New Jersey one long blast is required by state law when approaching a station (the result of spectators awaiting passage of the Robert Kennedy funeral train getting in the way of scheduled trains, resulting in some deaths). Two shorts from a standing train indicate an imminent forward movement, as does sounding the bell.