The term comes easily to American lips: robber barons. It's an effective phrase to conjure images of fabulously wealthy men doing pretty much as they pleased with people, resources, and the American landscape.
That is a start, but Pulitzer prize winning author Michael Hiltzik takes us a lot further down the track in his book Iron Empires: Robber Barons, Railroads, and the Making of Modern America. The railroad bosses and the financiers behind them did build much of the country's infrastructure, but frequently crashed the machinery of the US economy in the process.
We get a fuller picture from our 2020 interview with the author.