The incident occurred on board the Avadh Assam Express near Moradabad late Tuesday.
While five of the young men sustained minor injuries, one - Imtiaz Ali - suffered severe head injuries.
The youngsters told police that they rushed into the train as it was about to leave and unknowingly boarded a coach meant exclusively for army soldiers. By the time they realised they were in the wrong coach, the train had pulled out of the station.
The injured youth said the soldiers refused to heed their pleas that they would get off at the next station, and threw them out of the moving train, one by one.
The injured were identified as Imtiaz Ali, Guddu, Rauf, Pankaj, Patvai and Ravi.
No case has yet been registered against the errant soldiers.
A police official said the injured youth did not want to press further action, fearing even more trouble.