A police officer in Illinois tackled a teen moments before she was able to run in front of an oncoming train. Waukegan Police Officer Christopher Harris says his department received a call from the girl's sister, warning that she may try to harm herself. The authorities tracked the teen's cellphone to the area near a train crossing. Officer Harris saw the girl and twice told her to stop. She didn't. "That's when I just sprint after her and tackle her," Harris told InsideEdition.com.