There are lots of myths and legends surrounding the final months of the Nazi regime. Some say high ranking officials fled to a secret base built in the ice of Antarctica. Others claim Adolf Hitler survived his Berlin bunker and made it to South America. But one of the most enduring—and at least mildly plausible—stories is that at the end of the war, the Nazis hid an entire train full of guns, gems, gold and valuable art in a series of tunnels in a Polish mountain. Now, a pair of amateur researchers have begun digging at the site where they believe that treasure train is buried, the BBC reports, despite the fact that a team of geologists and engineers failed last year to find any trace of train in the location they're excavating.

As Danny Lewis reported for Smithsonian.com, locals near the town of Walbryzych in the southwest of Poland have a legend that an armored train full of Nazi loot was traveling out of the nearby city of Wroclaw in 1945 when the Red Army began closing in. The train disappeared near Książ Castle two miles outside of Walbrzych, and many believe it was sequestered in a series of tunnels in the Owl Mountains, with at least one German miner claiming that he saw soldiers wheeling the loot into the tunnel.

A year ago, Piotr Koper, a builder from Walbrzych, and Andreas Richter, a German genealogist, announced to the world that they had discovered a bill of lading (a receipt of shipment) detailing the train’s location. They even produced ground-penetrating radar images that appear to show tanks sitting on train cars in a tunnel beneath the ground. But imaging experts doubted the authenticity of the images. At the time, the Polish culture minister said he was “99 percent sure” the train has been found, Lewis reported in September. Researchers from the Krakow University of Science and Technology, however, spent a month using radar on the mountain, but failed to find anything like the purported train, and by last December, the story was reported as officially debunked.

But the doubt has not deterred Koper and Richter, who are continuing on with the privately funded effort, Rick Noack at The Washington Post. The duo along with a team of 33 others began excavating the area where they believe the train lies yesterday. The team is drilling three holes in the ground to probe for the train and hopes to have answers by Thursday.

“The train is not a needle in the haystack; if there is one, we will find it,” Andrzej Gaik, a spokesman for the search committee tells Agence France-Presse. “If we find a tunnel, then that is also a success. Maybe the train is hidden inside that tunnel.”

While academics and government officials doubt anything will show up, there are some reasons to believe Nazi loot and weapons may be stashed in the area. Hitler did order a vast system of underground tunnels to be built in the Owl Mountains. Thousands of prisoners of war constructed seven huge tunnels in the area as part of Project Riese (Giant), though the purpose for them remains unclear. The Nazis were also known to hide stolen art and treasure in underground salt mines and tunnels. So, while the story of the gold train remains unlikely, the treasure hunt chugs ahead.