Catherine Burns will be buried in her native County Tyrone in Northern Ireland on Sunday, 183 years after her attempt to create a new life in the United States came to a grim end in a railroad shantytown outside Philadelphia.

The identification of her remains, their return home, and the insight her story has provided into the lives of Catholic Irish immigrants who sailed to the US fleeing prejudice is the result of a remarkable history research project.

That project ultimately revealed Catherine’s murder more than a century and a half after it happened.

She was 29 years old and already a widow when she left home and sailed from Derry, County Derry, as one of 160 Catholic Irish immigrants bound for the US on a ship called the John Stamp. When they landed in Philadelphia, Catherine must have been hopeful. She soon found work with 57 other Irish Catholic immigrants at a railroad construction called Duffy’s Cut, 30 miles outside the city in the town of East Whiteland.

But the immigrants were dead some six weeks after their arrival in 1832.

For years, memory of the deaths was little more than a ghost story, and the name Duffy’s Cut had all but been forgotten. The place would be referred to as Dead Horse Hollow for many years. Newspapers at the time reported deaths along the railroad in the camp, but just eight, and all were attributed to the cholera epidemic that seeped south from New York City that year.

Then, 12 years ago, twin brothers and PhD historians Frank and Bill Watson inherited a file that upended that history – on Pennsylvania Railroad letterhead, memoranda recounted the deaths of 57 Irish railroad workers, not the eight reported by newspapers.

After years of work to corroborate the file, the Watson brothers pinpointed where they believed the remains of the railroad workers lay. Soon, they uncovered an unmarked gravesite where seven skeletons were buried in wooden coffins along the Amtrak tracks.

The skeleton they would later identify as Catherine – and the others with it – had gashes in their backs of their heads. One had an apparent bullet wound.

‘People panicked’

When the brothers found the remains, the impulse to disregard them was strong. Native American burial grounds were common in the area, and not two miles away, in Paoli, 52 revolutionary war soldiers were killed in a massacre during a British ambush.

At least one local historian mused that the bullet wound could have been the result of a musket accident.

But the Watsons persisted in their research over the years, drawing on more than half a dozen other disciplines ranging from geology to forensic dentistry in an effort to confirm their theory – that this was a mass grave of railroad workers from Philadelphia’s industrial revolution.

Not all 57 workers are believed to have been murdered – the Watsons and their colleagues believe as many as 50 more died when cholera swept the east coast that summer, an epidemic that may have precipitated the violence that befell their countrymen as townspeople tried to stop the disease from spreading.

“We both believe that when the epidemic hit, people panicked,” said Bill Watson. The epidemic had already killed 3,500 people in New York City, records from the time indicate. The Watsons are hopeful that the next phase of digging, on Amtrak property, will uncover more clues and, perhaps, remains.

Listed on the John Stamp’s manifest, Catherine Burns is thought to have worked as a cook or laundress in the shanty where workers lived, in the woods near the tracks. The worksite, called Duffy’s Cut, was named after Philip Duffy, a builder, himself Irish Catholic, who secured a contract with Pennsylvania to construct mile 59 of the Philadelphia-Columbia railroad.

A forensic dentist who analyzed Burns’s bones said she would have been a giant in her day, nearing 6ft tall. Like those of an athlete, Burns’s bones had grown accustomed to the burden manual labor placed on her body, growing dense as her muscles demanded greater fortitude with years of hard work. She is believed to have come to the United States with her father-in-law, a 79-year-old listed as a “laborer” on the John Stamp’s manifest.

The only other worker to be identified was 18-year-old John Ruddy, a man with a rare genetic defect that causes a missing molar. That allowed researchers to track him to a family of Ruddys now living in Donegal, many of whom have the same one-in-100,000 defect. The Watsons are working to find a lab that can perform a conclusive DNA comparison between John Ruddy’s genes and those of people believed to be his descendants.

But even as the Watsons and their close colleague and fellow historian Earl Schandelmeier III are embraced by Irish diplomats and Irish American organizations, the researchers’ work remains a subject of contention among some historians.

“The part that’s raw is the murder part,” said Jim Jones, a history professor at nearby West Chester University. “This is an area that prides itself on its tolerance – Quakers, the underground railroad and all that – and the idea that there may be murderous discrimination against foreigners, Irishmen in this case, certainly makes some people uneasy.”

Ghostly scene

The bodies of the workers found in the railroad fill would have remained there had it not been for the foresight of the Watson’s maternal grandfather, Joseph Tripcian.

Tripcian was the executive assistant to the president of the Pennsylvania railroad, a trusted man interested in history who was permitted to take archives from the company’s vault as he wished.

When the railroad went bankrupt in 1970, Tripcian took a file whose title betrayed its grim contents: “History of Duffy’s Cut stone enclosure east of Malvern, Pennsylvania, which marks the burial place of 57 track laborers who were victims of the cholera epidemic of 1832.”

The file had remained secret. Local newspapers of the time reported cholera deaths with the dry tone of a legislative summary, and reported that eight died along the tracks. Only a group of four nuns and one blacksmith nursed the men through their final hours, the newspaper reported.

Tripcian’s grandsons, meanwhile, would both receive doctorates in history. Frank, older by 10 minutes, works as a Lutheran minister in Tom’s River, New Jersey. Bill is a professor of medieval history at Immaculata University, a Catholic college not three miles from the dig site, where he secured a professorship years before he was acquainted with Duffy’s Cut.

It was at Immaculata that Bill Watson saw what is best described as will-o’-the-wisp outside his second story college office window – the group of neon lights hovered in a far corner of the college’s lawn, a phenomenon he didn’t understand but didn’t think of as suspicious. He would joke to a friend at the time that the lights were “somebody’s idea of art”.

Watson thought little of the odd sighting until Frank inherited his grandfather’s file two years later. When Bill Watson read the file he was flabbergasted – contained in the file was a description from 1909 of the supernatural lore that many locals have retold about the site, including a strikingly accurate description of the lights that Watson had seen from his office window years earlier.

The file describes a ghostly scene at “the fill”, where the tracks were built up by workers.

A sign at Duffy’s Cut mass grave commemorates the deaths of Irish immigrant workers. Photograph: Barney Quinn/PA

“So I trudged up between the stone blocks untill [sic] I got on to the fill, and there I say [sic] with my own eyes the ghosts of the Irishmen who died with the cholera a month ago,” local historian Julian F Sachse quotes an “old man” as saying in his 1909 retelling, typed on Pennsylvania Railroad letterhead. “They looked as if they were a kind of green and blue fire, and there they were a hopping and bobbing on their graves.”

As the years went on, the Watsons’ interest in finding the shanty site grew. Geologist Tim Bechtel used sophisticated tools to locate “anomalies”, and Schandelmeier built the findings into a map using complex software to pinpoint where the remains might be.

The Watsons went to the site with little more than shovels, some earnest Immaculata students and a small budget for pizza.

Now, after securing an analysis of the remains from University of Pennsylvania forensic anthropologist Janet Monge, the Watsons and their fellow researchers believe the seven men were killed when they attempted to flee the cholera-infected shanty.

The men were “held or tied up”, said Frank Watson, and “buried by their unsuspecting colleagues in the fill”. Their bodies were returned to the shanty in wooden coffins, each sealed with upwards of 100 nails to conceal the “bloody mess” inside. The brothers also suspect that an organization headed by some of the area’s most prominent families and designed to deter horse theft, the East Whiteland Horse Company, may have had the means to perpetrate such an act.

“Nobody gave a damn until we started finding stuff,” said Bill Watson, about digging up Barlow knives, the belly of a smoking pipe etched with “Derry”, and finally remains.

At one point, to have a state historical marker placed nearby, Watson was required to prove the worthiness of the event. “I had to prove the statewide or national significance of the death of 57 Irish immigrants,” he said, his indignation evident.

“Every single step of the way has been a battle.”

Even airlines have been uncooperative – the Watsons said a “human remains” department at one stage declined to help them transport Burns’s body.

The Watsons said they had to get a restraining order against one man when he insisted the researchers broke state grave laws. Eccentrics have claimed that maybe, perhaps, they are descended from families who came to Pennsylvania with the affluent quaker William Penn in 1682, but if there are any records of that grim day in 1832 they are certainly now destroyed.

The Pennsylvania Historical and Museum Commission refused to comment. A spokesman said the commission had no information about the incident. The Chester County Historical Society said it could draw no conclusions from the information it possessed.

Bits of wood remains from the coffin that once held Catherine Burns. On the right are bone fragments, which will be returned to Ireland. Photograph: Jessica Glenza/The Guardian

“I certainly buy that these seven guys were murdered,” said Harvard sociologist Jason Kaufman, who studied vigilantism between the civil war and first world war. “It seems to be, like, a guess as to who did it.”

Kaufman added: “Until well into the 20th century, the Irish are really second-class citizens, as are really Catholics … They were one tiny slice above blacks.”

The Watsons believe there is another mass grave nearby in Downingtown, Pennsylvania, near railroad mile marker 48, and perhaps as many as 1,000 mass graves across the north-east where laborers of the industrial revolution were buried where they worked.

After many years without digging, the Watsons, Schandelmeier and fellow researchers are on the verge of extracting core samples from beside the Amtrak tracks. They expect to find pieces of bone in the clay and dirt – evidence, they believe, of the remaining 50 men the secret file said died at the site.

If the men do come upon another mass grave, it would be just feet from where the previous seven bodies were discovered, in a wooded area behind a trim housing development marked by a stone enclosure made of the Philadelphia-Columbia’s first railroad ties.

Return home

Catherine Burns was buried at St Patrick’s Church in Clonoe, County Tyrone, on Sunday after a wake with music and dance.

“The people of the village have really connected with Catherine and there has been huge interest from parishioners in her story and the story of Irish emigrants,” parish priest Father Benny Fee told the BBC.