The Industrial Age from 1877-1900 saw rapid industrialization and economic growth in the United States driven by natural resources, expanding populations and capital investment. Key innovations like the light bulb, steel production, electricity and the telephone transformed industry and society. The railroad industry expanded rapidly during this period with help from government subsidies, opening up the West but also leading to exploitation of many workers. Large trusts and monopolies dominated industries like oil and steel, leading to calls for regulation of large businesses and protection of workers and consumers. Labor unions grew to advocate for workers facing long hours, low pay and unsafe conditions in the new industrial economy.