I find myself tempted to install one of these insane train horn setups on my truck.
Why? Because why not.
This rat hole is infinitely interesting.
Want to know what $12k worth of air horn sounds like? Of course you do: https://www.kahlenberg.com/model-q-4-chimetone-air-horn.html
Your cool $12k only gets you the trumpets. The air supply and control system is on you.
Designed for vessels from 70 to 200 meters, the trumpets only weigh 280lbs.