The New Castle Manufacturing Company, chartered in 1833 and located in New Castle, Delaware, is one of the very few firms in the state to have produced locomotives, and by far the most important.  Pictured here is a rare 1852 black-and-white lithograph of New Castle's twenty-ton locomotive "Philadelphia," built for the Philadelphia, Wilmington & Baltimore Railroad, later taken over by the Pennsylvania Railroad, now part of Amtrak.  The railroad network in the Mid-Atlantic region doubled in size during the 1850s, and the "Philadelphia" was one of dozens of steam engines constructed to meet expanding needs. She is of the 4-4-0 wheel configuration, the general purpose wood-burning locomotive used in America until the 1880s.  The "Philadelphia" was state-of-the-art for 1852 but would soon be outmoded as level cylinders, spread trucks, link motion valve gears, and other improvements radically altered locomotive design later in the decade.