Military power tends to be a function of economic power, and the British Navy was the essential capability for establishing the imperial sway - which was attuned to furnish the raw materials for the British manufacturing ascendance. So they were mutually reinforcing.

The Transcontinental Railroad Act is the first step in creating a continental common market.

I would speculate that a critical mass of the population has to internalize a middle class outlook first. International aid experience has demonstrated many times that just building railroads doesn't get you there. You need people ready to sue them.

No specific technology. My guess is that it was the instinct always to go to maximum scale. Great Britain kept much more of a small shop mindset well into the twentieth century, for instance.

After I finished the Tycoons - on post-Civil War development - I realized how much I didn't know about the first half of the century, even though there had obviously been an enormous amount of development, so I read about and thought about that for a couple of years before I decided I was ready for a book.

It may not be replicable: One of the hardest transition that a developing country can make is the transition to middle-class status. Governments have to let go, people start insisting on following their own lights, etc.

I've been in China enough to know that you shouldn't opine on it unless you speak Chinese and have lived there for twenty years. I wasn't pretending to be a China expert in that final chapter. I was just pointing, first to the parallels between Chinese behavior toward us and ours toward GB when we were at the same stage of development, and secondly to how much harder their development path is than ours was.