The extensive use of electricity, internal combustion engines and create a new transport was quickly applied to industrial production and contributed greatly to economic development. And the World War didn’t effect the United Stated that another reason improve the economic development in U.S. Chinese help U.S built the Railroad it is more easy for people cross from east to west.  At that time, east factory start to sell product to the west by train. Before Gold Rush, a lot of people start small business, because at that time things are very expensive, need ship from south America. And If people can’t find jobs in NY at that time,  they can take train to San Francisco find a job, in 1870s, people are looking for jobs. Black people start to leave to the west.

California is white man’s land,  Chinese have no right to stay at that time, and no right to live. And after they help U.S finished the first Rail Road in Utah in 1869 they have no place to go, and they didn’t get the pay for the ticket to go back to China. Then Chinese back to San Francisco, they become factory workers in 1870. but Chinese did more but earn less than the white, they don’t take others job, and they can’t, they only can do the same jobs people who don’t want.