To expand on Simon, J.P literally called up the heads of several railroads guys, and other important to industry men, to a meeting. At this meeting he railroaded the men (sorry, couldnt help myself

) and forced them into monopolies with each other. He also standardized much of what these guys did and how they would thus forth work and operate. At this time the world/U.S economy was small enough for one man to make such a difference, afterwards there would be no such man in hte '30's.