Is there a difference between "treble" and "triple"?

According to the Cambridge Corpus of American English, Americans strongly prefer triple as an adjective, noun and verb. British and Australian writers, on the other hand, seem to use both triple and treble, but with treble more frequent as a verb and triple as a noun and adjective.

Fowler distinguished between treble meaning that something had become three times as large in size, and triple meaning consisting of three parts, but that no longer seems a reliable guide, if it ever was.

(Adapted from ‘The Cambridge Guide to English Usage’)

I'm a British English speaker, and I think I agree with Russell: triple suggests three different things and treble suggests three the same. A triathlon would be a triple event (never a treble), but three successive wins would be a treble (rarely a triple). Analogously, a double of something would always be two the same; duple (though its rarely used outside technical contexts such as music and biology) would indicate two different things.