What was a significant factor in the labor shortage faced by the builders of the Transcontinental Railroad?

The significant factor in the labor shortage faced by the builders of the Transcontinental Railroad relates to high demand for labor in agriculture. During the time when the railroad was being constructed, the United States was undergoing considerable westward expansion, which increased the need for labor in agriculture. Many potential workers were drawn to agricultural jobs that promised better wages and potentially more stable employment compared to the often grueling and dangerous work of railroad construction.

Additionally, the period saw fluctuations in available labor due to various economic opportunities arising from the growing agricultural demands, which pulled workers away from railroad projects. This high demand for labor in agriculture directly impacted the pool of available workers for the railroad, making it more challenging to find enough hands to complete the monumental task of building the Transcontinental Railroad.

The other options, while they may impact labor markets in different contexts – such as the aftermath of World War I leading to different economic conditions, rising wages potentially attracting workers away, and restrictive immigration policies limiting the flow of foreign labor – do not specifically address the immediate context of labor supply issues faced during the construction period of the Transcontinental Railroad.