"The gold may not be in the train that has been found but in one of these better secured military trains. It is possible there are more trains in Walbrzych.
"There are discrepancies between maps of the area from the 1920s and the 1940s which suggests there are tunnels under the town which have never been found. Up to 1947, the Soviets were here and we do not know what they found."
Ksiaz castle, Schloss Furstenstein in German, was being prepared for Hitler's arrival right up to the end of World War II, with a study and en-suite toilet installed.
A comprehensive bunker complex based on the blueprint of the dictator's Berlin wartime base was also under construction when the fortress was over-run by Soviet troops in 1945.
Local politician Lukasz Kazek claims that just one-third of the vast tunnel network built by the Germans during World War II, dubbed the Riese project - German for "giant" - have been discovered, raising the possibility that several more trains could yet be unearthed.
Kazek, 37, who also works as a tour guide at the town's Wlodarz tunnels, part of the Riese network, said: "In this region there are a lot of treasures, because when the Soviet army arrived, the Germans had to flee but they thought they would be coming back."