The train drove through the neighborhood Bolan in Balochistan province when the bomb went off, according to a county official, Samiullah Agha. He said rescuers transported the injured to a nearby hospital and engineers were repairing the damaged railway tracks.
The explosion was so powerful that eight train cars derailed, Agha said.
No one immediately claimed responsibility for the attack, but both separatist and militant groups are active in the region. For more than a decade, Baluchistan has been the scene of low-level insurgency by ethnic groups Baluch separatists seeking autonomy from the Islamabad government or full independence
Pakistani militants also have a presence in the province, which borders both Afghanistan and Iran.