Kelly Xion gave birth to a healthy baby boy on the platform of the Bowling Green station on Manhattan's southern tip.
Two Fire Department paramedics were on hand to assist in the delivery, while straphangers and tourists gawked.
The woman had been waiting for a train to Brooklyn when her labor went into overdrive at around 3:40 p.m.
EMT Jerry Chatelaim tells the New York Post that by the time he and partner Thomas Loggins got to the scene, the baby was already crowning.
The delivery happened in a New York minute.
Afterward, mom and baby were recovering at a hospital a few blocks away.