The Nazi gold train could contain an ornate room crafted out of amber, gold and precious jewels which has been missing since it was looted during World War Two, it has been claimed.

Journalist Tom Bower, who wrote Nazi Gold: the Full Story of the Fifty-Year Swiss-Nazi Conspiracy to Steal, has said he believes there is a high likelihood the hidden locomotive is filled with art and precious jewels, rather than bars of gold.

But what he really hopes to find in the train discovered abandoned in a tunnel underneath a Polish mountain is the Amber Room, stolen from the Catherine Palace, near St Petersburg, in about 1941.

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Gift: The Amber Room (pictured in 1932) was a gift to Peter the Great from the King of Prussia in 1716

Splendour: It was put into the Catherine Palace, near St Petersburg, where it remained until the Nazis looted the grand residence in 1941, dismantling the room and taking it back to one of their castles

Speaking to Sky News, Mr Bower said: 'If it is an art train, there will be paintings, there will be perhaps diamonds, there will be rubies and precious stones and also, the one thing that's always been missing, the Amber Room.

'I think it is far more exciting to think perhaps that is in the train.'

The Nazis dismantled the room - thought to be worth about £250million - when they arrived at the Russian palace in October 1941.

The Russians had tried to conceal the grand room, a gift to Peter the Great by the King of Prussia in 1716, by covering it in wallpaper, but their plan was foiled.

The room was then taken by the Germans by rail to Koenigsberg Castle, in what was then East Prussia. Now, the castle is found in the city of Kaliningrad.

But it disappeared In January 1945, after air raids and a savage ground assault on the city.

While some claimed it had been destroyed in the raids, others reported seeing 40 wagons moving away from the castle under a cloak of secrecy after the city fell to the Red Army.

Disappeared: But the room was never seen again after 1945, and some suspect it was whisked away by the Nazis as the Red Army marched on East Prussia (pictured: the replica Amber Room)

HOW AN AMBER CABINET BECAME THE AMBER ROOM The Amber Room was originally just a cabinet, given as a gift to Peter the Great The Amber Room was originally supposed to have been an amber cabinet, a gift from Friedrich-Wilhelm I of Prussia to Peter the Great, who admired the work on a visit to his castle in 1716. But instead of a cabinet, it was decided to use the panels as wall coverings, surrounding them with gilded carving, mirrors and yet more amber panels. In total, the room used 450kg of amber, and was finally completed in 1770. The room was so fragile it had a permanent caretaker, and when the Russians tried to hide the crumbling walls behind wallpaper. But the Nazis knew what was behind the mundane covering, and went about dismantling the room - a process which took 36 hours. They believed, as a Prussian gift, it belonged to them. But the room, taken back to the castle where it had originally been created for Friedrich-Wilhelm, was never seen again after 1945. Some claimed it had been destroyed in the bombings, but others say the panels were spirited away by the Nazis keen to keep hold of their loot. But the Russians weren't willing to give up on this crowning glory, and began a replica in 1982. It took more than 20 years and cost more than $12million, but visitors to the Catherine Palace, near St Petersburg, can now see the grand room for themselves. Sources: Catherine Palace and the Smithsonian Advertisement

Found?: Journalist Tom Bower believes the room could be on board a train found hidden in a tunnel (like this one) near the city of Walbrzych, in Poland

Journey: It would have had to have travelled the whole way across Poland to reach the town

To Mr Bower, it is entirely possible the train may have made the almost 400-mile journey across Poland to Walbrzych, on the border with the Czech Republic.

'As the Russians advanced and the Allies came in from the west, there was a huge movement as the Germans sought to keep it for themselves,' he explained.

Initially taken with a grain of salt, the story has gained credibility after a culture ministry official said he saw a ground-penetrating radar image of the alleged train on which he could make out platforms and cannons.

'I'm more than 99 percent sure such a train exists, but the nature of its contents is unverifiable at the moment,' Deputy Culture Minister Piotr Zuchowski said Friday.