The incident took place at Adamapur village near Karbandiya railway station of the district, Government railway police (GRP) officials said.
The four mutilated bodies were found on the track at the wee-hours of today.
The bodies have been identified as Sonamuni Devi (30), Anjali (5), chanchali (3) and Baby (1) of Admapur village.
Preliminary inquiry suggests that the woman took the extreme step out of depression triggered by financial problem following death of her husband a year ago.