An infant suffered minor injuries this afternoon after a baby carriage rolled off a subway platform and plummetted onto the tracks below.

About 1 p.m., a mother and her baby girl ascended to the elevated platform of the Market-Frankford Line at 56th Street in West Philadelphia to catch an eastbound train toward Center City.

The mother, temporarily distracted, let go of the jogging-style stroller. In a split second, the carriage began to roll. It pitched over the lip of the platform and tumbled onto the rails.

With the carriage on the tracks, the mother instantly jumped from the platform and pulled the baby out. A man standing nearby took the child from her and another woman sounded the alarm on the platform's yellow emergency box.

The entire incident was captured on surveillance video.

"It's pretty dramatic," said SEPTA spokesman Andrew Busch. "It's scary, you see the stroller drop and it hits the track. There isn't a train coming, but it's a bit of a fall there from the platform."

EMTs arrived minutes later.

"Fortunately there wasn't a train in the immediate area so we didn't have to shut down the line," Busch said. "The way everyone reacted was exactly the way to prevent it from becoming a tragedy."

Check back with Philly.com for more details.

Contact Sam Wood at 215-854-2796, @samwoodiii or samwood@phillynews.com