I was recently creating a resource pack that included custom whistle sounds for locomotives, but ran into issues with the hardcoded values for whistle duration and random whistle probability causing the new sounds to play over each other because they were significantly longer than the default ones. I think it would be a nice addition to break these parameters out as configuration options to enable more flexible sound customization and control over random whistle behavior.

Shouldn't be too difficult, but not a big priority.