The complexity and scale of railroad operations and their uneven extension across the landscape created both intensive and extensive changes in American communities. These changes and connections are difficult to capture in their full extent. They are especially difficult to represent. In rural Virginia, on the Eastern Shore of the Chesapeake Bay, for example, an extension of the powerful Pennsylvania Railroad penetrated this remote region in 1884, connecting it to Philadelphia, New York City, and other major centers in the East.  The company engineered a massive harbor on the Bay coast where there had been nothing but a marsh. It developed and laid out new towns along the line, operated a steamship company to move freight from the new harbor to Norfolk, and sponsored new agricultural products in the region. Farmers switched production from corn and oats, products no longer viable because of rail connections to the Midwest bonanza farms, to sweet and Irish potatoes. Barrel making to transport the new products took off and local forests on the Shore were denuded.  Other changes were accelerated with the arrival of the railroad. The barrier islands along Virginia’s Eastern Shore held thousands of rookeries for tern, willet, and curlew.  Within a few years of the railroad’s arrival, these birds were hunted out and shipped on cracked ice to New York City where their feathers were used in fashionable ladies hats. Conservation laws followed, game preserves sprang up, and by the turn of the century the railroad brought ornithologists down the shore on weekends to search for the rare species. The market for hats, the Victorian culture’s fashions, the technology of ice making and shipping, and the proximity of the railroad conspired to bring substantial environmental changes. The railroad brought other powerful changes as well, such as segregation.

So, when the Pennsylvania Railroad's network reached the Eastern Shore of Virginia in 1884, the process recast the region’s infrastructure, population and settlement patterns, agricultural practices, labor opportunities, architectural preferences, and industrial development. Similarly significant, but widely varied and particular events took place when the railroads came to other places. For Benjamin Heber Johnson in Revolution in Texas: How a Forgotten Rebellion and its Bloody Suppression Turned Mexicans into Americans (New Haven: Yale University Press, 2003), the railroad brought massive social change to southern Texas, setting in motion new labor patterns of deep consequence. For William Cronon (Nature's Metropolis: Chicago and the Great West) the extension of railroads into the west create and sustain the dynamic relationship between Chicago and its rural hinterlands.

Information flow and demographic patterns only rendered the railroad's networks more complex and contingent.  A wave of immigrants in Boston, fresh orders for the steel mills of the Mahoning Valley, or a spring drought in Florida might mean high prices for Eastern Shore (Va.) or Long Island (N.Y.) potatoes while a bumper potato crop in the Kaw Valley, a textile strike in New York City, or floods on the Mississippi might depress the market.  The railroad made possible, as Alan Trachtenberg explained, "new spaces, new regions of comprehension."