In his well-known book, Railroads and American Economic Growth, Robert Fogel asserted that in 19th century America railroads produced a “social saving” of about “six-tenths of 1 per cent of national income.” 1 Fogel’s work, in common with that of many economic historians who responded to it, attempts to measure in precise numerical terms the importance of the railroad to America’s economy. Nevertheless, regardless of their direct quantitative impact, railroads played a vital part in bringing about and moulding the new industrial world which emerged in the United States after 1840. Railroads were the first large scale technical system which arose in America and as such they shaped the way Americans organized technology and had a profound impact on large scale business. In defining the way in which the United States responded to large-scale technical systems railroads may have their most significant contribution to America’s economic growth. This is a contribution that cannot be easily measured.