George Stephenson (June 9, 1781 - August 12, 1848) was an English civil engineer renowned as the "Father of Railways". In 1821, a parliamentary bill was passed to allow the building of the Stockton and Darlington Railway. The rails used for the line were wrought-iron, could be produced in longer lengths than cast-iron and were less liable to crack under the weight of heavy locomotives. Through experimentation he concluded that railways should be kept as level as possible. The railway was a success and he was offered the position of chief engineer for a wide variety of other railways. Many of the first American railroad builders came to Newcastle to learn from him and many locomotives were purchased from the Stephenson shops. He was farsighted in realizing that the individual lines being built would eventually be joined together, and would need to have the same gauge. The standard gauge used throughout much of the world is due to him. He contracted pleurisy and died, in 1848 at the age of 67.