Ha Ha Ha, fire truck!, its already a tick off our list.
Actually I did find a solution to the problem . A little cruel but necessary as we were loosing our minds having to hear a baby cry its gut out.
Now Rio is S$$$ scared of a LED toy gun which my girl has .You have to just show it to him and he does the poor bird is dying act complete with the horrible screech. You put it away , he is all normal and will give you a stinky alexandrine stare and you dare not get your fingers next to him at this time or else......
We got the gun out everytime we heard the cry and told him sternly to stop it. He got the idea pretty fast. We still hear the baby cry but its restricted to his morning monologues with his food bowls or his toys.
I am really not sure if it was the right thing to do but at least we have maintained our sanity.