MadSci Network: Science History |
If you are asking about the source of the sound, it's steam escaping through small holes. These holes were deliberately placed to put an upper limit on steam pressures inside the cylinders of the locomotive. If you are asking why we spell the sound "choo choo" that's a question for a linguist! Onomatopoeic word origins are a bit complex; for example, the "sound a dog makes" is, I gather, spelled rather differently in French and German than in English. Dan Berger MadSci Administrator
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