Kolkata Metro general manager has ordered an inquiry into the incident. (Representational)
Three people including one child were injured after a Railway Protection Force (RPF) constable's rifle went off, during change of duty at the Dum Dum Metro station.
At 2 pm, the constable was receiving the INSAS rifle from a colleague during change of duty.
The bullet ricocheted after hitting the floor at the station complex, Metro spokesperson Indrani Banerjee said.
"Splinters from the bullet hit a woman, her nine-year old son and a Metro employee," she said.
The woman, Sangeeta Basu and her son were waiting to buy tickets when they were hit by the splinters.
Both of them and a metro employee Niranjan Majumdar were rushed to nearby R G Kar Medical College and Hospital, Ms Banerjee said, adding Metro Railway's Chief Medical Superintendent Mihir Chowdhury and Principal Chief Operations Manager Satyaki Nath were there to provide logistical assistance.
The child was hit in one leg while the mother sustained splinter injury in one hand. Their injuries are not serious.
"The general manager of Kolkata Metro Ajay Vijayvargiya has ordered a high level inquiry into the incident and has assured stern action