 As the numbers of Chinese laborers increased, so did the strength of anti-Chinese attitude among other workers in the U.S. economy.This finally resulted in legislation that aimed to limit future immigration of Chinese workers to the United States, and threatened to sour diplomatic relations between the United States and China through the Chinese Exclusion Act.The Chinese came to California in large numbers during the California Gold Rush, with 40,400 being recorded as arriving from 1851–1860, and again in the 1860s, when the Central Pacific Railroad recruited large labor gangs, many on five-year contracts, to build its portion of the Transcontinental Railroad.