Footage shows the dad bringing his baby aboard the train in a carrier before setting the infant down in a seat near another passenger. He then steps out to take a puff of a cigarette on the station platform.
But suddenly the doors close behind him. As the train begins to pull out of the station, the father gives chase, trying to stop it.
Inside the car, video shows the passenger who was sitting near the baby also run to alert someone.
Fortunately, the conductor was notified and the train returned to the station, where the infant and father were reunited.
Officials said the child was never in any danger.