Arun Singh and his associate, both students, allegedly passed lewd comments and outraged the modesty of a woman who was travelling in the Metro with her in-laws, police said.
The woman was travelling from Central to Dumdum Metro station when the incident happened inside a compartment and they were warned by her accompanying father-in-law.
As the two started harassing the woman again after getting down, the father-in-law, who is also a Metro Railways official, stopped the duo from fleeing and handed them over to the GRP.
The incident happened close on the heels of a young woman falling from train at Belur station to escape from molesters. She is currently recuperating.