With the coming of the California gold rush in 1849, many gold seekers traveled west via Panama, crossing the isthmus on muleback. Vanderbilt had the idea of crossing Central America via Nicaragua, a route to California several hundred miles shorter than the Panama route. He invested in the American Atlantic and Pacific Ship Canal Company (later changed to Accessory Transit Company), which proposed to cross Nicaragua via the San Juan River, Lake Nicaragua, and a twelve-mile road (later to be a canal) to the Pacific. He built a fleet of steamers to run from New York and New Orleans, built docks on the coasts of Nicaragua and Lake Nicaragua, and improved the road to the Pacific. Soon the route was busy with traffic heading to California. The company prospered, and by 1853 Vanderbilt was worth an estimated $11 million.
John F. Stover, "Vanderbilt, Cornelius," American National Biography Online, February 2000, http://www.anb.org/articles/10/10-01678.html.