Cast iron used in rails proved unsatisfactory because it was brittle and broke under heavy loads. The wrought iron invented by John Birkinshaw in 1820 replaced cast iron. Wrought iron, usually simply referred to as "iron", was a ductile material that could undergo considerable deformation before breaking, making it more suitable for iron rails. But iron was expensive to produce until Henry Cort patented the puddling process in 1784. In 1783 Cort also patented the rolling process, which was 15 times faster at consolidating and shaping iron than hammering. These processes greatly lowered the cost of producing iron and rails. The next important development in iron production was hot blast developed by James Beaumont Neilson (patented 1828), which considerably reduced the amount of coke (fuel) or charcoal needed to produce pig iron. Wrought iron was a soft material that contained slag or dross. The softness and dross tended to make iron rails distort and delaminate and they lasted less than 10 years. Sometimes they lasted as little as one year under high traffic. All these developments in the production of iron eventually led to the replacement of composite wood/iron rails with superior all-iron rails. The introduction of the Bessemer process, enabling steel to be made inexpensively, led to the era of great expansion of railways that began in the late 1860s. Steel rails lasted several times longer than iron. Steel rails made heavier locomotives possible, allowing for longer trains and improving the productivity of railroads. The Bessemer process introduced nitrogen into the steel, which caused the steel to become brittle with age. The open hearth furnace began to replace the Bessemer process near the end of the 19th century, improving the quality of steel and further reducing costs. Thus steel completely replaced the use of iron in rails, becoming standard for all railways.
cast iron used in rails proved unsatisfactory because it was brittle and broke under heavy loads the wrought iron invented by john birkinshaw in 1820 replaced cast iron wrought iron usually simply referred to as "iron" was a ductile material that could undergo considerable deformation before breaking making it more suitable for iron rails but iron was expensive to produce until henry cort patented the puddling process in 1784 in 1783 cort also patented the rolling process which was 15 times faster at consolidating and shaping iron than hammering these processes greatly lowered the cost of producing iron and rails the next important development in iron production was hot blast developed by james beaumont neilson (patented 1828) which considerably reduced the amount of coke (fuel) or charcoal needed to produce pig iron wrought iron was a soft material that contained slag or dross the softness and dross tended to make iron rails distort and delaminate and they lasted less than 10 years sometimes they lasted as little as one year under high traffic all these developments in the production of iron eventually led to the replacement of composite wood/iron rails with superior all-iron rails the introduction of the bessemer process enabling steel to be made inexpensively led to the era of great expansion of railways that began in the late 1860s steel rails lasted several times longer than iron steel rails made heavier locomotives possible allowing for longer trains and improving the productivity of railroads the bessemer process introduced nitrogen into the steel which caused the steel to become brittle with age the open hearth furnace began to replace the bessemer process near the end of the 19th century improving the quality of steel and further reducing costs thus steel completely replaced the use of iron in rails becoming standard for all railways