The Chinese were brought in to build the transcontinental railroads mid-19th century.
from Wikipedia:
1885: On February 8, the first official intake of Japanese migrants to a U.S.-controlled entity occurs when 676 men, 159 women, and 108 children arrive in Honolulu on board the Pacific Mail passenger freighter City of Tokio. These immigrants, the first of many Japanese immigrants to Hawaii, have come to work as laborers on the island’s sugar plantations via an assisted passage scheme organized by the Hawaiian government.
Which is during the timeframe I mentioned. Right?