The incident took place between Kaniz and Mehemdabad railway stations yesterday morning, railway police said today.
The two youths from Bihar's Sundapur village- Rajiv Mahanto and Rakesh Mahanto, both aged between 25-30 years, had come to Ahmedabad to appear for a railway exam. They had boarded the Ahmedabad-Mysore express to go back home, they said.
One of the three unidentified persons, who were sitting next to them, snatched Rajiv's mobile after which they entered into a scuffle, railway police officials said.
The three youths threw the duo out of the moving train and Rajiv died on the spot, while Rakesh sustained injuries, they said.
A case was registered today in this connection at the Nadiad railway police and investigation is being carried out by its local crime branch wing.