steam whistle

For the "Steam Whistle" beer brand, see Steam Whistle Brewing A steam whistle is a device used to produce sound with the aid of live steam. The whistle consists of the following main parts, as seen on the drawing: the whistle bell (1), the steam orifice (2) and the valve (9).When the lever (10) is pulled, the valve opens and lets the steam escape through the orifice. The steam will alternately compress and rarefy in the bell, creating the sound. The pitch, or tone, is dependent on the length of the bell; and also how far the engineer has opened the valve. Some engineers invented their own style of whistling.
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Noun
1. a whistle in which the sound is produced by steam; usually attached to a steam boiler
(hypernym) whistle
(part-holonym) calliope, steam organ