Explain the new Bessemer and open-hearth technologies developed for the large-scale production of durable steel. What impact did the vast expansion of steel production have on transportation industries in the late nineteenth century?

The Bessemer process was the first inexpensive industrial process for the mass-production of steel from molten pig iron before the development of the open hearth furnace. The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron.