They are images of a nation in motion - of a country building its future with expanding railroads and industrial opportunities. These glorious black-and-white photographs, which have been released by the Library of Congress, reveal America reveling in its new-found productivity, at a time when steam engines and steamboats were forging the nation ahead. The images, taken between 1870 and 1920, capture the determination with which America tackled the new century - and how the country also began enjoying the fruits of the 19th century's industrial labour, in what was termed the Gilded Age.