Using other people's money is, as Joseph Schumpeter pointed out, what entrepreneurs do. "...risk bearing is no part of the entrepreneurial function. It is the capitalist who bears the risk. The entrepreneur does so only to the extent to which, besides being an entrepreneur, he is also a capitalist, but qua entrepreneur he loses other people's money."
I take this account from Harold Holzer, Lincoln at Cooper Union: The Speech That Made Abraham Lincoln President (New York: Simon & Schuster, 2004), 60-65.
For the system before the Civil War see, James E. Vance, Jr., The North American Railroad: Its Origin, Evolution, and Geography (Baltimore: Johns Hopkins University Press, c. 1995), 1-124.
This and the discussion that follows is from William R. Siddall, "Railroad Gauges and Spatial Interaction," Geographical Review 59 (Jan. 1969), 29-57.
Vance, North American Railroad, maps 114-15.
George Rogers Taylor and Irene D. Neu, The American Railroad Network, 1861-1890 (Cambridge: Harvard Univ. Press, 1956), 11-14, 35-41, 53-54.
Alfred Chandler, The Visible Hand: The Managerial Revolution in American Business (Cambridge: Harvard Univ. Press, 1977), 90-109.