(1 ene 1850 año – 1 ene 1880 año)
Descripción:
 In 1850 few if any U.S businesses had more than a thousand employees. By the early 1880s, the Pennsylvania Railroad alone employed almost fifty thousand people, and the size of the business called for organization and coordination on an unprecedented scale 
Añadido al timeline:
fecha:
1 ene 1850 año
1 ene 1880 año
 ~ 30 years