MAP ACTIVITY Map 12.1 Railroads In 1860 Railroads were a crucial component of the revolutions in transportation and communications that transformed nineteenth-century America. The railroad system reflected the differences in the economies of the North and South. READING THE MAP: In which sections of the country was most of the railroad track laid by the middle of the nineteenth century? What cities served as the busiest railroad hubs? CONNECTIONS: How did the expansion of railroad networks affect the American economy? Why was the U.S. government willing to grant more than twenty million acres of public land to the private corporations that ran the railroads?