The fast reactions of a railway police officer in northern India saved an elderly passenger from being crushed beneath a moving train last week.

Security camera footage filmed on April 2 at Madhopur station in Rajasthan shows the officer sprinting to help a commuter who slipped while attempting to board the moving locomotive.

The passenger is dragged along by the train and begins to fall into the gap between a carriage and the platform when the officer hauls him to safety.

Moments later, footage shows the commuter get to his feet clearly shaken but unharmed.

This is the nail-biting moment when an elderly man was saved by an alert cop from being crushed under a moving train at the Sawai Madhopur railway station in Rajasthan northern India.

The man had slipped off the footboard of the moving train and was dragged several metres before an alert cop pulled him away to safety.

The CCTV footage shows the horrifying moment the elderly man is dragged as he hangs on to the train but loses balance and falls as the cop tries to catch up with him in order to save him.

Half of his body is seen coming beneath the train when the cop who misses his mark then runs back and pulls him away from underneath the train thus saving his life.