John Edgar Thomson (February 10, 1808 – May 27, 1874) was an American civil engineer and industrialist. An entrepreneur best known for his leadership of the Pennsylvania Railroad (PRR) from 1852 until his death in 1874, Thomson made it the largest business enterprise in the world and a world-class model for technological and managerial innovation. The railroad's first Chief Engineer became its third President. His sober, technical, methodical, and non-ideological personality had an important influence on the Pennsylvania Railroad, which in the mid-19th century was on the technical cutting edge of rail development. The railroad was known for its conservatism and steady growth while avoiding financial risks. His Pennsylvania Railroad became the largest railroad in the world, with 6000 miles of track, and was notable for generating steady financial dividends, for high-quality construction, constantly improving equipment, technological advances (such as replacing wood with coal as locomotive fuel), and innovation in management techniques for a large complex organization. Childhood and early career John Edgar Thomson was born in 1808 in Springfield Township, Delaware County, Pennsylvania, near Philadelphia, to a family with Quaker roots whose immigrant ancestors had arrived in the colonial era. His father John Thomson was a leading civil engineer, who helped build the Chesapeake and Delaware Canal and the first experimental railroad in the United States. The son had little formal schooling, as was typical of the time. He worked closely with his father from an early age, acquiring a sound foundation of engineering practice which he augmented by reading, observation, and experience. Thomason began his railroad career at age 19 as a rodman working in a survey crew locating the Philadelphia and Columbia Railroad; later he worked for Camden and Amboy Railroad. In 1832 he sailed to Great Britain, making an inspection tour of the new railways constructed in the country. Through his father's influence, he became a member of Pennsylvania state's engineer corps, surveying routes for a rail line west from Philadelphia. He was soon promoted to assistant engineer, and in 1830, when the line of the Camden & Amboy Railroad was located across the state of New Jersey, Thomson was placed in charge of an engineering division. Developing Georgia's railroads At the age of 26 in 1834, Thomson was hired as the chief engineer of the newly chartered Georgia Railroad. He located the road, negotiated and oversaw construction contracts, operated portions as they opened, and promoted