I don't know enough about tinnitus but you're probably right.
OT.
He’s not I’m afraid.
Exposure to any type of noise can cause problems. Loud, not so loud, sudden, prolonged, high pitched, low pitched. It affects everyone differently.
The general idea is that sounds above a certain volume for prolonged periods of time can cause long term damage to hearing. The louder it is the less exposure you need before damage could occur. Think of it like radiation.
For those who already have hearing loss or other conditions then lower amounts of exposure than necessary can cause temporary issues.
Our ears are more sensitive at certain frequencies. They’re designed to hear speech so these ‘shrill’ sounds appear louder but it doesn’t necessarily mean they’re doing less damage.
Using normal foam ear plugs isn’t really a sensible option as a long term solution as you change the way you hear things. If you have sensitive hearing then custom made plugs with an attenuation level you choose should be the way to go. These lower the volume but without drastically altering the sound so you can still hear people speak without it being muffled.
Back almost on topic.
I agree that this shouldn’t happen. There is potential for the volume to be unacceptably high and most are set up very poorly so any form of limiting is set incorrectly.
I agree that you should say something, for it can hurt people’s hearing, and could damage equipment which simply would not be replaced as quite often there is no system in place for efficiently testing this at stations of on trains.
I don’t agree you should take any equipment and do any measurements of volume levels for 2 main reasons. 1) the staff wouldn’t understand the results (and wouldn’t be expected to) rendering the activity pointless and 2) the level of accuracy would be so low that the results would be meaningless. How many times does this happen? What reference level are you comparing this to? It’s all well and good saying I measured the whistle noise and it was 108dB A weighted, but what was the level before and after. If the level was 72dB before then this is a huge difference but a busy station full of people with glass walls can be well into the 90s anyway. But 108 might only be 102 if the people weren’t talking. And where is the measurement done? 1m from a speaker? 2m from a speaker? It’s half the volume now. To test this you’d need several days and several hundred tests from different points, a figure made from one test is sadly meaningless.