"My view of where it's best to be in terms of production/distribution is summed up by Vanderbilt's railroad career. He bought a run-down, worthless road because it controlled the only rail line into Manhattan. The lesson: find the choke point and take it." https://www.gurufocus.com/news/130435/what-makes-a-good-business …
That's what Buffett did with the port of Los Angeles and bnsf (one minor detail: there are two railroads not one leaving Americas biggest port system)