Final answer:
The construction of the First Transcontinental Railroad involved crossing the Rocky Mountains, utilizing Irish and Chinese labor, building track from west to east, completing construction after the end of the Civil War, and meeting at Promontory Point, Utah.
Step-by-step explanation:
The construction of the First Transcontinental Railroad had several aspects:
1. It crossed the Rocky Mountains. This was a challenging task due to the rugged terrain and harsh weather conditions.
2. A large number of Irish immigrants were utilized in the construction going westward. They played a crucial role in building the railroad.
3. The Union Pacific Railroad primarily used Chinese labor to construct their portion of the railroad. Thousands of Chinese immigrants were employed for this massive undertaking.
4. The Central Pacific Railroad built track from west to east. They started from Sacramento, California, and worked their way towards Omaha, Nebraska.
5. The construction was completed after the end of the Civil War. The First Transcontinental Railroad was officially completed on May 10, 1869, when the Union Pacific and Central Pacific railroads met at Promontory Point, Utah.