According to police, Sudhir Singh Chouhan, who is a constable with the Army, was headed to his hometown Gwalior after he came to know of his younger brother Dharmendra's death when the incident took place near Sadar Bazar railway station on Sunday morning.
The scuffle took place on board the Jat Jamnagar Express. Sudhir's badly injured limbs had to be amputated at the army's base hospital in the city.
According to police, as the said train was packed, Sudhir had chosen a spot near the entrance to a compartment and placed his luggage nearby.
"All of a sudden, a boy started tugging at his shirt with the intention of snatching his mobile phone. They got into a scuffle during which Sudhir as well as the boy slipped and fell off the running train," a police officer said, adding that the snatcher had managed to flee with the phone.
Sudhir was later referred to the army's base hospital at Delhi Cantonment where both his legs had to be amputated, the officer said, adding that he is out of danger now.
Police said they have registered a case in this connection and have questioned several persons, but the suspect is yet to be identified.