The expansion of railroads was made possible because of the Steel industry.
When the tremendous growth of Steel industry took place in 19th century, as a result of a strong technological foundation, steel became a crucial element for rapid expansion of urban infrastructure; which also closely included the expansion of railroads. Due to steel highways, the lives of millions of people were improved through the use of railroads which supplied the expanding U.S. cities with food, fuel, building materials and access to markets.