PROSPECT HEIGHTS - An alert subway operator slammed the brakes in time to save the life of a teen who had jumped down to the tracks after dropping her cellphone Thursday afternoon.

Devone Mason says she slammed the emergency brakes when she saw a girl jump onto the tracks.

The 17-year-old was waiting at the Bergen Street station when her phone fell to the tracks around 2:30 p.m., according to officials.

She jumped down to retrieve it just as a train came barreling down the tunnel.

The operator saw the teen and slammed the emergency brakes. The train stopped, and the teen only suffered minor injuries.

A common MTA public service announcement tells straphangers to never go onto the tracks for any reason.

"I don't care what you drop down there, don't try to go get it," Mason says. "It's not worth it. I mean if I was going any faster we may not be having the same result we have."