NEW YORK (CBSNewYork) — A quick-thinking subway operator helped save a baby on Thursday after her stroller rolled onto the tracks.

It happened just before 9:30 a.m. at the 72nd Street and Broadway station. Police say the 8-month-old’s father was waiting for the 1 train when the brake on the stroller malfunctioned.

1 train tracks where child’s stroller rolled due to malfunction. (credit: CBS2)

Suddenly, the stroller rolled forward and down onto the tracks. Investigators say the father jumped down to the tracks with another person and saved the baby.

Fortunately, the child escaped with only a bump on her head. Parents nearby say it’s just another example of why you need to be extra-careful underground.

“You gotta stay away from the ledge,” Jonathan Rivera said. “You have to protect your daughter, your son, your loved one… always.”

Officials say the motorman on another track saw what happened and quickly alerted everyone, likely ensuring a happy ending to a dangerous situation.