Steam locomotives greatly improved during the 1800's increasing both their efficiency and speed. In the 1850's and during the Civil War in the United States the average speed was about 15 to 20 mph depending on grade and load pulled. General Haupt who oversaw the United States Military Railroads in the 1860's would budget 15 mph for scheduling purposes. In Great Britain at this time the invention of the steam orifice and the introduction of superheating increased the average speed to about 35 to 40mph. From the 1880's on greater engines, increased efficiency and the adaption of steel rails pushed the average passenger express to 50mph. At the very end of the 1800's speeds of 70 mph on passenger expresses were common in England and the Union Pacific on straight runs in the American West. At the very turn of the century The Santa Fe ran a specially modified train with one passenger car at 100 mph through parts of the American West in a speed run from Los Angeles to Chicago.