whistle

Whistles come in a variety of designs, But I guess the most important consideration is. Do you really want someone (maybe a child) walking around blowing a whistle all the time.

They can vary both in design and the number of holes used. Train type sounding whistles are often three or four holes, thus combining different sounds together to create the effect.

As can be seen below. For a train whistle type of sound, multiple holes are used, these whistles are often seen rectangular, but they work well as a turned whistle. The holes are each different in length, and the ‘D’ shaped plugs are adjusted and marked prior to being glued into place.