Seventy years ago, it is rumored, an armored train departed for the Polish city of Walbrzych in the waning days of World War II. It snaked stealthily through the thickly forested mountains of southwestern Poland, carrying an untold fortune in Nazi loot: gold, jewels, art, maybe even weapons confiscated from Polish citizens and sent into the interior for safekeeping as the German regime began to crumble. But the train never arrived.

Instead, it's thought to be sealed inside one of the tunnels built by slave laborers for the Nazis, who were occupying a castle just above the underground network. And there it remained, the subject of rampant speculation and several investigations that brought locals no closer to the train and its riches - if they even existed in the first place.

The latest report of discovery came in August, when two treasure hunters said they'd determined the location of the train based on a map drawn by a man on his deathbed.

But their claim doesn't seem to have panned out. On Tuesday, experts from Krakow University of Science and Technology said that a month of magnetic and gravitational surveys has revealed no trace of an underground rail system or the treasure train.

Project leader Janusz Madej said the scientists did find some anomalies, but they were just eight feet below the surface - not deep enough to be anything matching descriptions of the train's hiding spot.

"There may be a tunnel," Madej said at a news conference, "but there is no train."

Piotr Koper and Andreas Richter, the amateur explorers who claimed to have located the train four months ago, were less convinced by the scientists' findings. At the same news conference, they said their own research team had found further proof of the train's existence: images from ground-penetrating sensors that showed clear signs of a tunnel laid with tracks and sleepers and several shapes below ground that could only be the fabled vehicle.

"We carried out similar examinations in many other locations, but we have never encountered anything like this," Koper said, according to the New York Times. "There is no way these shapes are of natural origin."

The pair acknowledged they are only hobbyists - Koper is a Polish construction company owner, Richter a German geologist - but said they stood by their claims. "There can't be a mistake," Koper said.

"It's human to make a mistake," Madej responded. "But it's foolish to stand by it."