I was just playing a word game, one so old that I've forgotten the name for it. In this particular case I meant to point out that in the case of America-or any other New World country, I suppose-is that a long list of "-ation(s)" can probably be made and that we can amuse ourselves with picking a "most important" but that it was a synergy between all of them, not the preeminence of one of them, that guaranteed the outcome. Imagine a room full of people sitting in a big circle and in their turn each speaks about the single key to building America. After every speaker finishes, heads nod and opinions change until at last every element has (almost) equal weight.
There isn't any question that transportation by rail and waterway are critical, even today.
Both of my Grandfathers were allowed into the US because they were builders: A stone mason and an engineer.