It happened somewhere between mile 92 and 119.

The Chinese railroad workers were grading and digging tunnels across a stretch of the Sierras when they decided to lay down their tools. It was the end of June 1867 and snow still covered the mountain tops.

The men, many of them from Canton in southern China, had demands: They wanted pay equal to whites, shorter workdays, and better conditions for building the country’s first transcontinental railroad.

So they put them to their employer, the Central Pacific Railroad, and a strike was on.

“This project, the railroad, going through the mountains was the largest engineering project in the country at the time,” Hilton Obenzinger, associate director of the Chinese Railroad Workers in North America Project at Stanford University, told NBC News.

Chinese laborers working on the Central Pacific Railroad. Alfred A. Hart Photograph Collection / Courtesy of the Chinese Railroad Workers in North America Project at Stanford University

“And this work stoppage was the largest labor action in the country at that time,” he added.

This month marks the 150th anniversary of the historic eight-day strike, which began on June 25. It ended after Central Pacific director Charles Crocker choked off food, supplies, and transportation to thousands of Chinese laborers who lived in camps where they worked.

While the railroad made no concessions, Obenzinger said the action helped counter the image that the Chinese were docile and wouldn’t fight for their rights.

“They learned that the Chinese could not be taken for granted,” he said.

“Everybody knows Chinese worked on the railroad, there’s a paragraph in every textbook. But that’s about all they know — and that’s what we’re trying to correct.”

Chinese laborers made up a majority of the Central Pacific workforce that built out the transcontinental railroad east from California. The rails they laid eventually met track set down by the Union Pacific, which worked westward.

On May 10, 1869, the golden spike was hammered in at Promontory, Utah.

Hiring Chinese began as an experiment after a January 1865 advertisement seeking 5,000 laborers netted only a few hundred, Obenzinger said. Those who took the jobs did so for a time, eventually heading to the Nevada silver mines for better wages and the prospect of striking it rich, he noted.

Facing a labor shortage, Crocker suggested recruiting Chinese, a group that earlier had worked on the California Central Railroad and the San Jose Railroad, according to the Chinese Railroad Workers in North America Project. They also had history as strike breakers when Irish masons walked off the job, Obenzinger added.

But Crocker’s plan hit opposition amid anti-Chinese sentiment, stemming from the California Gold Rush, that gripped the state. Among those against it was construction superintendent James Strobridge.

“He didn’t think they were strong enough,” Obenzinger said.

Strobridge also worried the whites wouldn’t work alongside the Chinese, according to Obenzinger.

But Strobridge yielded and the Central Pacific tested out 50 Chinese workers in 1865, Obenzinger said. They were among the 50,000 to 60,000 Chinese living in California that year, hailing from Sacramento, San Francisco, and the gold-mining towns of the Sierra Nevada, according to Obenzinger.

The experiment a success, the railroad hired additional groups of 50, but the Chinese labor pool in California soon ran out, Obenzinger said. So the Central Pacific arranged with labor contractors to bring workers directly from China, he said. They arrived by boat beginning in July 1865.

Two years later, between 80 and 90 percent of the Central Pacific workforce was Chinese; the rest was of European-American descent, mostly Irish, Obenzinger said. Some 8,000 Chinese focused on building the tunnels while another 3,000 laid track.

A letter from Leland Stanford, former governor of California and president Central Pacific, requesting additional labor to work on rail lines. Courtesy of the Chinese Railroad Workers in North America Project at Stanford University

By contrast, the Union Pacific had no Chinese and was overwhelmingly Irish, according to Obenzinger.

Disparities between Chinese and white workers set the stage for the June 1867 work stoppage. The Chinese had seen a pay increase from $31 to $35 per month by Spring 1867, but it fell short of the $40 monthly salaries whites were pulling in, Obenzinger said.

They were also toiling longer hours, often under dangerous conditions, whipped or restrained if they left to seek employment elsewhere. And unlike whites, the Chinese had to foot the bill for their lodging, food, and tools, according to the project.

When the strike went down on June 25, 1867, some 5,000 Chinese were at work between the California towns of Cisco and Truckee, just west of the Nevada border.

As far as job actions go, this one came with little drama.

“They went to their camp and they sat,” Obenzinger said. “Crocker was amazed. He reported that if there had been that number of white laborers on strike, it would’ve been impossible to control them.”

But Crocker was also concerned.

“They felt if they did concede, the Chinese would be bossing them,” Obenzinger added.

An 1867 article from the Daily Alta California newspaper detailing the end of the strike.

The strike was also cutting into profits. Both the Central Pacific and Union Pacific were paid through government subsidies by how many miles of track they laid down, according to the project. Speed translated into dollars, and the workers knew this.

Reports at the time suggested the Union Pacific may have orchestrated the job action to disrupt the Central Pacific’s momentum, though Obenzinger said there was no evidence of this.

As the standoff wore on, an idea was floated to bring in recently freed slaves as strike breakers, according to the project. Crocker, meanwhile, took the step of cutting off all food and supplies to the Chinese laborers, hoping that starvation would force them back to work.

It did.

“Charles Crocker, superintendent of the Central Pacific Railroad, who returned last night from the work at Summit and Truckee River, reports that with exception of one or two gangs, all the Chinamen have resumed work,” reads a July 3, 1867, article in the Daily Alta California. “No increase of pay, except increase made before the strike or decrease in time, has been allowed them.”

In the months after the golden spike was driven, Chinese workers hired by other railroads staged a few smaller job actions over not being paid, according to the project.

Chinese were also sent elsewhere across the country to build new lines. In some states, such as Washington and Texas, Chinese encountered hostility, according to the project.

The 1867 strike was one of a number of actions taken by Asian Americans and Pacific Islanders, who have a long history of being active in the labor movement, according to executive director Alvina Yeh of the Asian Pacific American Labor Alliance, a national labor organization.

Yeh pointed to Filipino and Japanese sugar plantation workers striking in Hawaii, as well as labor actions by Chinese garment workers in San Francisco and New York City, all of them happening in the 19th and 20th centuries.

“I think that our community continues to fight in many different kinds of cases for better wages and a safer workplace,” Yeh told NBC News.

Chinese railroad workers with lanterns and flags at the Dutch Flat Railroad Station area. The Placer County Museum via the Chinese Railroad Workers in North America Project at Stanford University

In the end, the Chinese never got pay parity with the Irish while building the transcontinental railroad, Obenzinger said. But their strike a century and a half ago was not necessarily in vain. Obenzinger said they believe the Chinese, to some degree, eventually won many of their demands.

“There’s some evidence that the abusive treatment was lightened up...it was thought that they were able to make progress,” he said.

Yeh said failed strikes have also benefitted advances in the overall labor movement.

“No matter what, even if strikes are ultimately unsuccessful, I think it tells an important story about how workers continue to be exploited in the country for profit and how they continue to organize,” she said.

“This project, the railroad, going through the mountains was the largest engineering project in the country at the time. And this work stoppage was the largest labor action in the country at that time.”

Unanswered questions remain about the 1867 labor action. Obenzinger said they are working with Irish-American historians to learn, for instance, whether any Irish stood in solidarity with the Chinese. The Irish, after all, were known as a group that fought fiercely for their rights, taking unscrupulous employers to task.

That Stanford University has undertaken this project also holds significance.

Leland Stanford, a wealthy former California governor who ran under an anti-Chinese immigrant platform, was also president of the Central Pacific. The railroad made Stanford even richer, and to honor their son who died of typhoid fever, the Stanfords later founded the school that bears their name.

Some Chinese even worked on early construction of the university’s foundations, Obenzinger said.

“Whereas he [Stanford] spoke out against the Chinese, in a lot of instances he spoke very highly of the Chinese,” Obenzinger said. “It was a mixed bag.”

A funeral procession of Chinese railroad workers near Dutch Flat, California. Courtesy of Placer County Museum via the Chinese Railroad Workers in North America Project at Stanford University

As the first transcontinental railroad prepares to mark 150 years since its completion in 1869, Stanford researchers are still working to unearth more details about the lives of the Chinese who accomplished one of the greatest American engineering feats of the 19th century.

Part of that includes taking oral histories from descendants of Chinese railroad workers, Obenzinger said, in an effort to learn what they know of their ancestors and what happened to their families.

“Everybody knows Chinese worked on the railroad, there’s a paragraph in every textbook,” Obenzinger said. “But that’s about all they know — and that’s what we’re trying to correct.”

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CORRECTION (June 21, 2017, 1 p.m.): An earlier version of this article misstated that the Chinese railroad workers did not encounter tension in Washington State. The Chinese faced violence during the Tacoma riot of 1885.