The world will know within “three or four days” whether a legendary Nazi gold train lies buried in a secret railway siding in south-west Poland, a team of treasure hunters has claimed.

On Tuesday, excavations with heavy equipment began on a railway embankment close to the southern city of Walbrzych, despite independent research concluding they will find only soil and not the fabled train.

According to local legend, the train and its cargo of bullion disappeared into the mountains around Walbrzych as the Nazis fled the advancing Red Army in 1945.