Gizmodo has a really cool "vintage monorail gallery"..
And, yes, of course the Disneyland Monorail is there, but so are some others I hadn't see.
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The one to the left here was from the 1964 World's Fair. It is totally cool.
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There are some really really old ones (including a doulbe decker 1876 built for the nation's centenital) - and the oldest was a Irish one that looks silly.
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But I really like the ones below.
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They say that "teachnically" this "rail plane" isn't a monorail since there is a guiderail below. But it is too cool not to include.
This is an early Seattle demonstration rail. Cool, huh?