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During the 19th century, the railroad frog was fabricated from standard carbon steel rail. During this period, there were many designs for the rigid frog from riveted plate frogs to the current AREA standard rigid frog. In the late 1800s, however, R.A. Hadfield of England developed "Hadfield Manganese Steel." The unusual properties of this manganese steel, as well as its toughness and ability to withstand severe impacts, made it most suitable for railroad service. The first manganese steel castings were made for street railway frogs. The success of manganese steel in the street railway castings led to its use in steam railway special work frogs, crossings, and switches. By the first decade of the 20th century, the rail-bound frog was introduced to the American railroads. Since then, the rail-bound manganese frog has progressed through many design improvements. Currently, there are new designs being developed to meet the needs of the heavy-haul railroad.
Is that it? Hadfield manganese steel?
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