I've been reading a book that was highly recommended here on HN a few months ago: "Nature's Metropolis", and just finished a chapter that explains this. Back i

I've been reading a book that was highly recommended here on HN a few months ago: "Nature's Metropolis", and just finished a chapter that explains this. Back in 1868, there were essentially just two rail networks in the US - the eastern half and the western half. They met in Chicago. The operational model was very different, and the presence of Great Lakes shipping (with low summertime shipping rates) kept either side from trying to expand to be truly nationwide. In essence, a timetable relative to Washington D.C. showed Sacramento just as an example. No railroad went from D.C. to anywhere west of Chicago. Not only did you change trains, you changed railroad companies.