All three died on the spot and the bodies were shifted to the district hospital, police said.
A 27-year-old woman committed suicide by jumping in front of an oncoming train along with her two minor sons in Rajasthan's Dausa district on Friday, the police said.
The children too died in the incident which occurred near Lalsot flyover, they said.
The woman, Seema Kumari Meena, jumped in front of the Pooja Express along with Vikas, 6, and Aryan, 4, they said.
All three died on the spot and the bodies were shifted to the district hospital's mortuary for a post-mortem examination, they said.