Warsaw - The location of a train full of Nazi treasure has been promised to Polish officials - just as soon as its discoverers get a guarantee of a 10% finders' fee.The Polish internet news portal daminfo.pl reported on Wednesday that two residents of the south-western community of Walbrzych had discovered an armoured train car full of Nazi gold, but were keeping its location to themselves until they knew they would be able to cash in.The site posted a copy of the notice the treasure hunters gave to the town. City officials would not confirm or deny the discovery.Speculation about Nazi treasure abandoned in Poland has sparked interest several times since the end of WWII, only to be debunked as a fable."This is a regular topic," local historian Joanna Lamparska told TV broadcaster TVN24. She said rumours have persisted for years about an abandoned train car in an underground shaft. Stories have often revolved around an abandoned train car crammed with treasure somewhere between Breslau and Walbrzych."It would be an unbelievable discovery," said Lamparska, but noted "No one has ever been able to confirm the existence of this train."That did not stop online news portal wiadomosci walbrzyskie from speculating that the train was packed with up to 300 tons of gold. Jaroslaw Chmielewski, the attorney for the treasure hunters, only ramped up the speculation with comments on Wednesday to Radio Wroclaw."This is a discovery of global importance, comparable to that of the Titanic."An underground Nazi complex, known as Riese (Giant), did operate near Walbrzych during WWII. It is believed that significant portions of the complex's industrial operations were moved underground as aerial bombardment picked up towards the war's end.The contents of the train car are unknown. Speculation ranges from gold, to stolen valuables, to precious raw materials.