The first Prussian train that is shown in the movie looks differently that the one that was used in real life in 1838. The chimney was on top of the engine, not in front of it and there were more spaces for passengers. Furthermore parts of the passenger seats had a cover above them.
The first Prussian Railway didn't arrive in Berlin from Potsdam-Zehlendorf until the 29th October 1838, not the 1st September as said in the movie. Furthermore the first part of the railroad in Zehlendorf was opened on the 22nd September 1838.