Re: "The next generation of network was the railway"
Didn't say the canals weren't Big Engineering (having done a bit of Industrial Archaelogy I can bore you to tears on the subject) and yes they had a pretty big impact but they were not next gen: they were an extension of already apparent engineering principles. Of course, cast-iron meant that stronger and larger bridges could be built but most aqueducts were still granite/wood and puddle clay affairs with the appliance of a bit more thought and more construction.
By no means the same effect as the invention of the steam locomotive/iron rail/consequent speed-between-distant-towns combo.
As far as canals go, there's a natural progression from boats on rivers, ditch-digging and bridge-building. First known navigable canal was around 510BC - not new.
Aqueducts started around the same time (although water-carrying ones admittedly) - not new and a couple of the ones into Rome are still being used.
Navigable ones in the late 17th - not new
Locks - the Chinese some time - can't be buggered to look it up. - not new.
We joined all the dots and improved locks, summit canals, aqueducts in the 18th.
Yes, a gap of a few centuries that perhaps makes it look like a big leap but there was no impetus for us to do it until the industrial revolution brought the need: many of the resources were inland. Up until then there was no reason for county or national scale projects. Not enough money and not enough people either!
But still, from a technological point of view, canals really are only boats floating down a man-made river. (Sorry for the disjointed sentences, I'm only half concentrating on this).