There is a Canadian National line that is approximately a mile, but not visible, from our house. We have noticed that some engineers do the full grade crossing honks, while others seem to sound a few "tired" honks at the crossing. Since we can't see the train we don't know if its traveling five or fifty miles an hour, crossing visibility profile is not great, and there can be full sound or honks at midnight or daylight, almost seemingly engineer's choice.
We were under the impression that all trains had to do the full cadence regardless of visibility or time of day/night.
What say you professional engineers