"Two men have surrendered to the police today. They were arrested and later released on bail," a police official involved in the investigation said.
The duo maintained that they are innocent and did not know the other two accused, who are still absconding, he said.
A second year BCom student had alleged harassment by the four on October 12 while she was returning home on board the train around 8pm.
The girl had also complained that guards at the Metro Rail and its management had not helped her.