I decided to get a train whistle for my grandkids. I wanted one that sounded more like a train than anything I could find commercially. It took me a long time and many iterations. I designed this around the notes for K5LA Amtrak whistle (B,D#,F#,G#). I added and Extra "B" to get the five notes. I think it came out pretty well. I added names to mine but I left this one generic.