Sources: Railroads and the Making of Modern America, University of Nebraska, Lincoln (Rail Network). US Census Bureau (Urban Population).
In only 30 years after its introduction, the American rail network totaled about 28,900 miles (46,500 km) on the eve of the Civil War (1861-1865). Yet, the American rail network was composed of two systems reflecting the political division between the North (Union States) and the South (Confederate States). Outside a connection through Washington, the networks were not connected and serviced rather different economic systems. This lack of connectivity was compounded by the fact that railways servicing the same city were often not connected, requiring ferrying cargo from one terminal to the other and for passengers to spend a night to catch the next day train (schedules were not effectively coordinated).
The dominantly rural society of the South was mainly serviced by penetration lines seeking to connect the agricultural hinterland to ports where surpluses were exported (e.g. New Orleans & Charleston). As such, the network was not very cohesive. The more urbanized North developed a network based on interconnecting its main urban centers and agricultural regions in the Midwest in a complex lattice. At the end of the Civil War, the expansion of the network would resume as well as its level of integration.