Trestle Work and Engine No. 2 by the Union Pacific, on the Eastern Approach to the Promontory Summit

Photograph, 1869
Andrew Joseph Russell, American, 1829–1902

Much of the engineering know-how used on the Transcontinental Railroad was developed during the American Civil War, including railroad construction and bridge building. This improved engineering was best illustrated in Utah during the last days leading up to the wedding of the rails. 

In the final months before May 10, 1869, both the Central Pacific and Union Pacific were grading and laying track, often within throwing distance of each other, both vying for the same federal certification that brought large sums of borrowed federal funds and land grants. The Union Pacific built this trestle in 36 days, finishing it five days before the May 10th ceremony. What is not shown in this photograph is the Central Pacific's competing "Big [earthen] Fill" roadbed which was built 70 feet high and 500 feet across, 200 yards away, over the same ravine.

Image courtesy of the Union Pacific Railroad Museum

Why build a railroad across 1,900 miles of land?

Building the Transcontinental Railroad transformed many aspects of life in the United States. A rail line spanning the continent facilitated commerce and westward expansion, fulfilling the then-popular notion of Manifest Destiny, or the belief that Anglo-Americans had the God-given right to expand west.

The Transcontinental Railroad was an engineering feat that has had long-lasting impact on how we live our lives today. Expansion of the railroad enabled changes—among them shortened travel times, direct access to Asian markets, and the ability to expand the military into the West—that would have been unimaginable at the time to some.

"An act to aid in the construction of a railroad and telegraph line from the Missouri river to the Pacific ocean, and to secure to the government the use of the same for postal, military, and other purposes....”

— Pacific Railway Act, July 1, 1862