As the boy's grandmother stood on the platform at a Melbourne station, the pram rolled off the platform into the path of the oncoming train, The Melbourne Herald Sun reported Wednesday.
Train driver Steve Ryan applied the emergency brakes then dismounted from the engine cab and pulled the child from under the train, the newspaper said.
"It's got me … how he survived," Ryan said, adding he thought of his own grandchild as the near-tragedy unfolded.
"I just jumped in and started doing it on instinct because of my granddaughter.
"You're trained and know this sort of thing could happen," Ryan said. "When it does your instincts just kick in. Whenever I approach a platform I always look out for school kids and prams."
Similar incidents have raised concerns about the safety of older station platforms, which slope towards the tracks.
Since 2004 new platforms are built to slope away from tracks, the Herald Sun said.