The blast took place inside bogie number nine of the Rawalpindi—bound Jaffar Express when it arrived at Sibi station, Dawn online reported.
Federal MInister for Railways Khawaja Saad Rafique said a woman is suspected to be behind the attack.
The blast completely destroyed the bogie and resulted in a fire that spread to other coaches in the train.
Rescue and emergency teams shifted the injured, including women and children, to various hospitals.
Due to the absence of surgeons and shortage of medicine, some victims were shifted from the Sibi Civil Hospital to Quetta.