initially a 9 miles gravity railroad with animal powered return of cars, is built between Summit Hill Railroads and Canals of the United States of America by Henry V. Poor (New York: John H. Schultz & Co, 1860), pages 415,537  and Mauch Chunk (now Jim Thorpe), Pennsylvania when rails are laid on top of the existing mule-haul road graded to be nearly uniform in grade from its establishment in 1819-20.<ref