The youngster was recently named Time’s Person of the Year but that didn’t stop the outspoken teen from criticising the firm. She told transport firm Deutsche Bahn that she had been forced to sit on the floor of the train. However, the business hit back by claiming Greta had a seat in first claim.
This week she has been challenging delegates at the UN’s COP25 summit.
She claims that the leaders had not done enough abut climate change.
The incident on the train occurred as she returned home from Germany to Sweden.
On Twitter she wrote: “Traveling on overcrowded trains through Germany.
It comes after Melania Trump caused outrage after refusing to condemn her husband Donald Trump after he attacked Greta.
There has been an ongoing row between the US President and Greta.
The two frequently spar on social media platform Twitter, playing out their arguments to millions of people.
And despite championing against online cyber bulling and helping children through her controversial BeBest campaign, Melania supported Donald.
A statement via the FLOTUS’ press secretary said: “BeBest is the First Lady’s initiative, and she will continue to use it to do all she can to help children.
“It is no secret that the President and First Lady often communicate differently – as most married couples do.
“Their son is not an activist who travels the globe giving speeches.
“He is a 13-year-old who wants and deserves privacy.”