With its new status and strategic location, Sacramento quickly prospered and became the western end of the Pony Express. Later it became a terminus of the First Transcontinental Railroad, which began construction in Sacramento in 1863 and was financed by "The Big Four"—Mark Hopkins, Charles Crocker, Collis P. Huntington, and Leland Stanford. Both the American and especially Sacramento rivers would be key elements in the economic success of the city. In fact, Sacramento effectively controlled commerce on these rivers, and public works projects were funded through taxes levied on goods unloaded from boats and loaded onto rail cars in the historic Sacramento Rail Yards.