An unarmed Coast Guardsman was patrolling the beach in Long Island, New York, the night of June 12, 1942, when a submarine bearing German markings glided toward the shore. Under cover of darkness, four men took to a raft, equipped with boxes of explosives and tens of thousands of dollars in American cash.

The men, dressed in partial naval uniforms, were German spies sent under Adolf Hitler’s orders to sabotage U.S. industry. Among their targets: the tight railroad curve in the mountains outside Altoona.

“It’s a hidden history in the area,” said Penn State Altoona history instructor Jared Frederick. “The industrial capacity of Altoona was a very high priority.”

The story of Operation Pastorius – the failed Nazi plot to ravage American industry and wreak havoc on the war effort – is set to be told this weekend at the Horseshoe Curve National Historic Landmark. Starting at 9 a.m. today and noon Sunday, the “Guarding the Curve” weekend features World War II re-enactors and presentations on the plot that brought the Nazis closer than ever before to an attack on U.S. land.

Brought to our knees

Wearing naval equipment to avoid execution as plainclothes agents, the English-speaking saboteurs reached the Long Island beach in time to bury their explosives and secret papers. Trained outside Berlin and promised pensions for their families, they were ordered to pose as ordinary Americans as they prepared to bomb factories and railroads across the eastern United States.

Pennsylvania was high on Germany’s target list. The Nazi high command had named an aluminum-processing plant in Pittsburgh, a propeller factory in Beaver and a tank factory in Berwick among their goals, according to writer James P. Duffy’s book “Target: America.”

In fact, the operation’s name, Pastorius, was taken from Francis Daniel Pastorius, founder of Pennsylvania’s first permanent German settlement. The mission was intended to slow the American war machine, and in the network of railroads that carried troops and weapons to port, few points were more strategically important than the Horseshoe Curve that carried trains over the Appalachians.

Roughly 8,700 freight cars passed through nearby Gallitzin every day in 1942, Hollidaysburg-based author Dennis P. McIlnay wrote in “The Horseshoe Curve.”

“With supply and troop trains added to the already heavy traffic, trains were rounding the Horseshoe Curve on an average of one every 15 minutes,” McIlnay said.

That made the Curve an appetizing target for the German spies.

Just three months earlier, Life magazine had run a story detailing possible Axis invasion plans, complete with maps and illustrations of German bombers laying waste to American cities. Its title: “Now the U.S. must fight for its life.”

It wasn’t just alarmist reporting: With the United States only a few months into the war and its industrial muscle just beginning to show its strength, German submarines were wreaking havoc on shipping just miles off the coast. For those living on the East Coast, the war had already come home as tankers and transport ships burned and sank in plain view.

“America can be brought to her knees,” the U.S. ambassador to the Soviet Union said at the time.

The plot uncovered

Changing into civilian clothes on the Long Island beach, the saboteurs hid their explosives – including the TNT that, as McIlnay wrote, they planned to wire to detonators under the Curve’s tracks.

When a train passed, he said, the line would explode, derailing cars and disabling the strategic Altoona line.

The scheme hit a bump, however, when a Coast Guard patrolman came upon the group. One of the spies, George Dasch, pressed $260 into the guard’s hand and told him to forget the encounter, German magazine Der Spiegel later reported.

The guardsman let them proceed to New York City but quickly reported the meeting to his superiors.

With investigators poised to unearth their German-marked bombs and naval uniforms, Dasch and a co-conspirator soon decided to turn themselves in and scuttle the mission.

“Though initially skeptical of his story, the FBI interrogated Dasch, who quickly revealed everything he knew about the plot and his co-conspirators,” according to a review of the case in the Vanderbilt Law Review.

Within two weeks of their landing, the four Germans – and four other agents who’d landed in Florida – were in federal custody. In August, less than two months after their mission began, the spies were found guilty.

Dasch and Ernst Burger, his fellow informer, were given long prison sentences. The remaining six were swiftly executed by a Washington, D.C., electric chair and buried in a potter’s field.

The German mission may have ended quickly and brutally, but the fears they stoked in Altoona would last for years as the war dragged on.

Defense and suspicion

At the Curve, police and city officials moved to stop infiltrators even before the German spies had crossed the Atlantic. In an Altoona Mirror article dated January 1942, less than two months after the Pearl Harbor attack, a city parks official ordered the Curve closed to all but soldiers and rail workers.

“City and railroad guards will be stationed at strategic points to keep cars and sightseers moving,” the article said.

When news arrived from the FBI that the plotters had intended to blow up the Curve, the city and the Pennsylvania Railroad stepped up efforts to guard the site: County police officers patrolled the Altoona rail shops while “special watchmen” stood watch at the Gallitzin tunnels, according to contemporary news articles.

“For years, it was only PRR workers and military personnel that had access to the site,” Frederick of Penn State Altoona said.

Workers posted 1,500 signs around the Curve warning against trespassing; “Loose talk can cost lives,” some read.

For Altoona’s substantial German population, particularly those working on the railroad, fear of infiltration quickly turned to personal suspicion as federal and state authorities worked to dismantle suspected spy networks, Frederick said. McIlnay’s book details the “custodial detention” FBI Director J. Edgar Hoover advised for Pennsylvania Germans suspected of involvement.

Within days of the saboteurs’ arrests, agents raided 225 Altoona homes and dragged residents to the 11th Avenue post office for interrogation, Frederick said.

“They raided these homes in anticipation of finding (allies) that the German saboteurs may have had,” he said. “Since the Horseshoe Curve was on the hit list, they may have had fellow saboteurs already living here in the city.”

In his book, McIlnay said he could find little information on the raids that targeted Altoona’s Germans.

Frederick said the shame of attacking the city’s own residents – many of whom were allegedly turned in by friends and co-workers, regardless of innocence – has likely helped bury the story of the Nazi threat against Altoona.

The Germans would never again attempt such an ambitious sabotage landing, and despite talk nationwide of submarine-launched missiles and super-long-range bombers, the Curve wouldn’t face a direct attack again. In May 1946, a year after the German surrender, the site reopened to the public, Frederick said.

Today, few remember the war scare and the sabotage trials. For Frederick, a World War II re-enactor, the weekend’s events could help shed light on a nearly forgotten time in Altoona’s history.

“It is something that was shoved under the rug of local consciousness,” he said.