h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

It's a pity that Monorails tend to be used as a tourist attraction rather than a real public transport system, because they might actually be useful.
But they do have one fatal flaw: they can't easily be switched from one track to another (since they are clamped around the track, rather than sitting on it).

This is actually a supposed flaw. In practise it is not to difficult to create a monorail switch. Rather than having cross overs as on normal two rail track a whole section of track is moved. They managed it quite well with the Listowel and Ballybunnion Monorail using a turntable.

Modern monorails just move track sections, some in a linear fashion but others with a mechanism like a revolver.