If you have a topic pertaining to air horns, steam whistles, steam sirens, or other signals born from the industrial revolution, check out the new sister forum to this board:
http://www.horn-whistle-board.com/
Mature and insightful posters only please. There are many intelligent folks at Horn & Whistle board that can answer most of your questions on horns and whistles.
Note: This is a new site that replaced the original www.hornwhistleboard.com website