Thirteen coaches of the Patna-bound 12741 Vasco Da Gama- Patna Express jumped the rails near Manikpur Railway Station in the early hours, killing at least three passengers and leaving nine injured.
The deceased included a six-year-old boy and his father.
Adityanath has also declared Rs 50,000 for each of the seriously injured and Rs 25,000 for those who suffered minor injuries, an official release said.
Expressing grief over the death of passengers, the chief minister conveyed his sympathies to the families of the victims and wished speedy recovery to those injured.
The railway ministry has announced a compensation of Rs 5 lakh for the kin of those dead and Rs 1 lakh for those who suffered grievous injuries.