The heart-stopping moment a pram rolls onto tracks at Sydney train station

Transport NSW has released heart-stopping CCTV of the moment a baby in a pram rolls onto train tracks in Sydney's west.

The mother-of-three had just exited a lift at West Ryde station when she realised one of her children was stuck inside.

She turned back to help the child but had forgotten to put the brake on the pram, which rolled forward and tipped onto the train tracks.

Fortunately fellow passengers were able to help her lift the pram off the tracks before the next train arrived.

Miraculously, the baby was uninjured from the fall.

The vision has been released to coincide with a new campaign designed at improving safety on the state's public transport system.