R N Mahapatra, CPRO Eastern Railway, said the train left Sealdah station at 03:20 AM and reached Titagarh station at 03:55 AM. The blast took place just after a person boarded the train at Titagarh station.
He said of the 14 injured, seven were discharged after being given first aid while seven others were admitted to a nearby hospital.
Security has been beefed up to ensure passenger safety, he said, adding that the incident appeared to be the outcome of group rivalry.
The railway police were investigating the incident which appeared to be a crude bomb blast.