The best of these are by Maury Klein; see esp. Klein, Union Pacific
Maury Klein, Union Pacific, (Garden City, N.Y.: Doubleday, 1987).
Gerald Berk, a political scientist, has recognized this, as has William Roy, a historical sociologist.
William Roy, Socializing Capital: The Rise of the Large Industrial Corporation in America, (Princeton: Princeton Univ. Press, 1997), 95;
Quote, Adams to Moorfield Storey, Feb. 2, 1885, UP, PO, OC, vol. 27, ser. 2, r. 23;
for policies during the Civil War, Heather Cox Richardson, The Greatest Nation of the Earth: Republican Economic Policies during the Civil War (Cambridge: Harvard Univ. Press, 1997), 170-72, 175, 178-80.
Although scholars until recently have emphasized the comparative weakness of the American state, the federal government was hardly weak between 1860 and 1876. The classic work here is Richard Bensel, Yankee Leviathan,
Richard Bensel,
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.