The three factors that transformed industry during the Gilded Age were new technology, new business practices, and the expansion of railroads. New technology during this era included innovations such as the telephone, electric light, and assembly line production methods. These advancements greatly increased productivity and efficiency in manufacturing and communication. New business practices involved the rise of large corporations, trusts, and managerial strategies like vertical and horizontal integration, which allowed businesses to operate on a much larger scale and dominate markets. The expansion of railroads connected isolated regions to national markets, facilitated the transportation of goods and raw materials across the country, and helped create a national economy. Railroads also spurred the growth of other industries like steel and coal. Together, these three factors drove rapid industrial growth and economic transformation in the United States during the Gilded Age.