I have an original Lionel 2332 GG-1 from 1947 with the “door buzzer” horn. It works as well as it’s ever going to. Is there a way to replace or upgrade it with a better sounding horn? This item is a family piece and will never be sold, so I’m not terribly concerned with preserving its originality.
Without going into the hi dollar figure you could try getting the sound board that lionel uses in their classic’s engines. It has a horn and bell, easy to install and remove if you ever changed your mind.