"[This site] explores the dynamic social change that came between 1850 and 1900 with the growth of railroads, telegraphs, steam ships and other technologies. It concentrates on the railroad network, and explores how the railroad's expansion and development brought profound economic, social, and political changes." Title from home page (viewed June 3, 2009). This collection includes shapefile data representing railroad networks in the United States from 1840 to 1870. Mode of access: World Wide Web.