On May 10, 1869, a few short years after the Civil War, two railroad trains met nose-to-nose at Promontory Summit before a cheering crowd. The occasion marked the completion of America’s first transcontinental railroad – a monumental feat of innovation, engineering and manpower that connected east and west and forever transformed a young nation.

Nearly 1,800 miles of track connected our country’s coastal cities to the rural interior, opening up new markets and creating an economic boom that helped transform America into a global economic power.

The transcontinental railroad employed a workforce that was a diverse conglomeration of Chinese immigrants, Civil War veterans from North and South, Mormon settlers, Irish immigrants, African-Americans, Native Americans, and others who worked together on this difficult, dangerous and daunting project.

At this year’s 150th anniversary commemoration of the Golden Spike ceremony marking the completion of the transcontinental railroads, we salute all the workers who built the transcontinental railroad.

The story of the Chinese laborers who worked on the transcontinental railroad is an especially poignant one. Tasked with building the railroad from the West, the Central Pacific Railroad hired 15,000 workers, of whom approximately 12,000 or more were Chinese immigrants. They blasted and chiseled their way through the rugged Sierra Nevada mountains, some of the most difficult and dangerous work of the entire project.

Using manual hammer drills, pickaxes and explosives, they dug tunnels through hard granite. Snow fell so deeply in the mountains that they had to build roofs over 37 miles of track so supply trains could make it through. The conditions were dangerous, merciless and harsh, and an estimated 500 to 1,000 workers of Chinese heritage lost their lives. But they persevered.

One of the four developers of the Central Pacific Railroad noted that the early completion of the transcontinental railroad was due in no small part to the “fidelity and industry” of the Chinese workers. This accomplishment occurred despite the fact that the Chinese workers were not given the opportunity to bring their families to this country, or to become American citizens.

These workers could never have imagined that one day, our country would be as diverse as it is today. As the first Asian Pacific American woman appointed to the President’s cabinet — and the first American of Chinese heritage to serve as U.S. Secretary of Transportation — I am especially sensitive to this historic occasion to fully recognize the historic contribution of the Chinese laborers to the building of the transcontinental railroad.

The transcontinental railroad created the ability to move people and goods across the continent more quickly and at much lower cost, which led to explosive economic growth and prosperity for America. The benefits were felt not only in the big coastal cities, but in the rural interior, which gained access to new markets.

The transcontinental railroad was a visionary infrastructure project that transformed our country in a manner every bit as consequential as the digital revolution that binds the world together today. Over the course of the 150 years since it was completed, innovators continue to dream bigger and find faster, safer and more efficient ways to travel by rail.

Steam engines have given way to diesel and electric locomotives. Telegraph wires have been replaced by satellite and wireless communications. Manual track laying has been replaced with automated track-laying machines. Hand operated brakes have been replaced with connected air-operated brakes. And what was once a dangerous, injury-prone, high-risk industry is today one of the safest modes of transportation.

All this is due to the determination of these intrepid transcontinental railroad workers who made possible one of the most consequential infrastructure projects in history that opened a new chapter for America.

Elaine L. Chao | Secretary of Transportation

Elaine L. Chao is secretary of the U.S. Department of Transportation