Why were the Chinese important in the construction of the Transcontinental Railroad?

From 1863 and 1869, roughly 15,000 Chinese workers helped build the transcontinental railroad. Chinese workers made up most of the workforce between roughly 700 miles of train tracks between Sacramento, California, and Promontory, Utah.

explanation:

japan participated in world war i from 1914 to 1918 in an alliance with entente powers and played an important role in securing the sea lanes in the west pacific and indian oceans against the imperial german navy as the member of the allies.