Indian railway officials say human error may be to blame for Tuesday's collision between two passenger trains that killed nine people and injured nearly 100 others.

Authorities are still investigating the cause of the accident, which occurred at a train station near the port city of Chennai in southern India.

Southern Railway General Manager Deepak Krishnan said Wednesday that the driver of a moving train that crashed into a stationary one apparently ignored signal and speed restrictions.

He says the driver survived but is badly injured after jumping out of his train before the crash. Tests show the driver was sober at the time.