An Indian railway worker has been hailed a "superhero" after he sprinted more than 30 metres along a track to grab a boy from the path of an express train.

CCTV images of Mayur Shelke's incredible rescue have gone viral on social media with many lauding the selfless 30-year-old.

The six-year-old boy was with his partially sighted mother on Saturday at Vangani station -- about 70 kilometres (about 42 miles) east of Mumbai -- when he fell off the platform edge onto the track.

Shelke was alerted by cries for help from the mother and immediately started running along the track.

He is seen in images released by the Indian Central Railways grabbing the boy, throwing him back onto the platform and then climbing up himself barely two seconds before the Udyan Express thundered through.

"I saw the kid falling and the train speeding towards him. There was no chance he would have lived had I not intervened," Shelke was quoted as saying by the Mid-Day newspaper.

He said he had been scared of the looming train, but added: "There was no time to think at all, I was determined to save him."

Fatal accidents are common on India's vast, but often dilapidated railway network.

Social media users called Shelke, whose job as a pointsman is to check the train signals, a "superhero".

Railway Minister Piyush Goyal said Shelke would be rewarded for "motivating humanity with his work".