Deutsche Bahn has apologized for the embarrassing incidents that made headlines across the country.
In the fourth such expulsion in three weeks, a 12-year-old schoolgirl was made to leave a train an hour's ride from home because she could not pay a 40 euro ($50) fine.
"It is purely foolish to react in such a way," said Karl-Peter Naumann, director of the passenger organization Pro Bahn. "Banishing them from the train is inhumane and causes unnecessary problems."
German newspapers had already condemned Deutsche Bahn on Tuesday after a 14-year-old was told to leave a train because her ticket was only valid later in the day.
Earlier, a 13-year-old and a 12-year-old were also forced to leave trains. One child had to carry her cello 5 km (3 miles ) home in the dark while the other was left on a platform with no money or mobile phone.
Wednesday, Deutsche Bahn said all ticket inspectors would have to sign an agreement promising not to banish children from trains if traveling alone.
"Everybody should know that it is unacceptable to throw children off the train," a spokesman told the TAZ daily.
