The woman, a Bhopal resident, yesterday called up the Dabra Superintendent of Police from the train and threatened to commit suicide as her lover's marriage had been fixed with someone else, Railway Protection Force Inspector Satyendra Yadav said.
The SP immediately informed Railway Police following which, RPF personnel searched the train at Mathura station and brought the woman to the police station where she fell unconscious, he said.
She was rushed to the district hospital as police suspected she consumed some poisonous substance.
Police suspect that the woman was under depression as her lover's marriage was fixed.
The woman had also filed a complaint of rape and cheating against her lover in Bhopal earlier.
She is undergoing treatment at the hospital, the Inspector said, adding her family has been informed about the incident.