I am curious as to how and why it ended up in Poland, and where exactly it was being stored.
There's a bit more about the search for them in
this article. It looks as if the operator of that Orient Express went bust in 1970, and they would have been sold to whoever offered the administrators money for them, and stored wherever it was cheap while they tried to flog them off. And further transits through the hands of administrators would not be a surprise. After all, how would you recognise a reputable dealer in unwanted old rolling stock?