Here is a video of the whistle I built with an engineer from the Durango to Silverton narrow gauge railroad. It is the same proportions as the whistles used on the Union Pacific 4-8-8-4 Big Boy locomotives but smaller dimensions. I do have one that is an exact replica but I don't have it hooked up. ...

Here are a few more for us whistle lovers.

https://www.youtube.com/watch?v=xFl8s-23lJM

Hmmm. I thought I heard three. Might have been the screech of one chime changing tones once it hit its frequency.
Way cool just the same.

Here is a letter I found while researching Hedbergs.

Deep, rich toned three chime whistle.
I think I peed a little.

Here is the Hedberg working in my driveway. I'm not sure how to post a video so I've put it in as an image and as a URL.

http://pages.suddenlink.net/acfarer/sirenscall.avi

I'll give it a shot. It screams using my battery pack for jump starting cars.

Good day all.
Found a Hedberg the other day. Most likely from a fire truck. Runs well on 12V.
Can anyone attest to the scarcity or value?