Final answer:
The Chinese laborers did most of the work on the transcontinental railroad.
Step-by-step explanation:
The group of laborers that did most of the work on the transcontinental railroad were the Chinese.
During the construction of the Transcontinental Railroad in the 19th century, thousands of Chinese immigrant laborers were hired by the Central Pacific section to lay rails across the Sierra Nevada mountain range.
These Chinese workers, along with other non-White workers, were often given the most difficult and dangerous jobs, such as blasting rocks and drilling tunnels.