The image is indelible — the meeting of the Central Pacific No. 119 and Union Pacific 60, aka The Jupiter, at Promontory Summit in 1869. It was a defining moment in our nation’s history.

Now, as we mark the 150th anniversary, the transcontinental railway offers up lessons for those who listen and serves as an inspiration for what we could hope to achieve.

On the simplest level, the driving of the “Golden Spike” unified a nation — literally and figuratively — that, just a few short years outside of the Civil War, was far more divided than we can comprehend today.

Its completion was marked with celebrations from coast to coast. The hammers meant to drive the final spike were outfitted with wires that would register the event via telegraph to Omaha and Sacramento, but the rail boss who swung the hammer missed. It turns out, swinging those hammers wasn’t easy. But the real spike was eventually driven into the ground.

Like so much of our nation — then and now — the railroad was built by migrant laborers unwanted in much of the country except for their ability to work.

Francisco Kjolseth | The Salt Lake Tribune The Salt Lake Tribune staff portraits. Robert Gehrke.

It was an amalgamation of the Chinese migrants, Irish who escaped famine, newly freed slaves and Latter-day Saints driven West to flee religious persecution who laid the 1,800 miles of track, humble people of modest means willing to do backbreaking labor.

The Chinese workers were paid about two-thirds what the Irish rail workers received and were often tasked with the most dangerous jobs, like being lowered in baskets to blow holes in the sides of the mountains. By most estimates, a thousand people were killed in the process, and those who survived were denied U.S. citizenship.

In addition to the iconic photograph of the trains meeting at Promontory, celebrants hoisting champagne bottles (which were cropped out of some later prints of the photo), there is another image. This is one of eight Chinese railroad workers laying the last rails to complete the line moments before the Golden Spike ceremony.

They were there. They were just not seen.

It is vital, said Max Chang, a board member of the Golden Spike Foundation, to “widen the lens” of history.

Chang was recently invited to tell the story of these workers to a class of mostly Latin American and South American students. The teacher, he said, felt like the students needed to hear the story “to understand that other groups have gone before them and faced similar situations.”

Racial prejudice and mistreatment weren’t the only tarnish on the Golden Spike. The project was plagued by corruption and self-dealing. The coming of the railroad led to the eradication of the bison and hastened the conquering of the Plains Indian tribes.

Like so much of our history, the railroad’s story needs to be understood with context and nuance. The threads that weave their way through the history of the railroad across 150 years are relevant today. We are, it seems sometimes, a hopelessly divided nation, grappling — then as now — with inequality and challenges.

Still, we have it in ourselves to accomplish remarkable things. A century after the completion of the transcontinental railroad, the nation came together to celebrate again, this time sending a man to the moon.

“That day we didn’t care what political party we were, we didn’t care what race we were or gender,” Chang said. “We didn’t care because we all did this together.”

There is inspiration in those grand achievements and a challenge to keep dreaming, because our divisions fall away when we can unite behind a great purpose. Then anything becomes possible.

“The greatness of America is never behind us,” Chang said. “It’s always ahead.”

So what is the next impossible thing we will accomplish?