Why was the construction of a railway to the Pacific important to Canada after Confederation?

The construction of a transcontinental railway was essential to Canada’s development following Confederation for several critical reasons:

• National Unity and Expansion: To maintain the vast territory extending from the Atlantic to the Pacific, it was necessary to physically link the country. The railway served as the "spine" that connected scattered former British colonies into a single, cohesive nation.12
• Securing British Columbia: A primary condition for British Columbia joining the Dominion in 1871 was the promise of a rail connection to the east within 10 years. This was also motivated by a desire to protect western Canadian interests from the influence of American railroads and to manage the influx of prospectors from the United States.23
• Sovereignty and Security: The railway was vital for ensuring Canada's independence from the United States. It also provided a necessary means to transport military forces rapidly to the northwest, as demonstrated during the Riel Rebellion of 1885, which proved the line's strategic value to the government.1