Although the contents of the train are unknown they have claimed a finder's fee of 10 per cent of the value of the find.
"We are outraged that all the rights to the find have been claimed by these two men," the society said in a statement. The society said it not been informed of the train's apparent discovery until August 31.
In response Mr Koper and Mr Richter issued a statement expressing their "regret" they had not been informed about the meeting on their expulsion and claimed that "personal interests had got in the way of common sense".
Their expulsion came as the Polish Army concluded an initial inspection of the site, and a report on its findings is due to be presented to the country's Defence Ministry.
"We will act professionally and calmly," said Tomasz Siemoniak, the Polish Defence Minister when questioned about the train by journalists. "We will also keep the public informed.
"At the moment it is too early to say what steps will be taken next," he continued, adding "I don't know if there is a train there."