CHICAGO (CBS) — Every year some 800 to 900 property thefts are reported on CTA trains. Most of the stolen items are iPhones or other electronic devices.

The thefts, as CBS 2’s Mike Parker reports, follow a familiar pattern, a pattern you should know about.

Jennifer Wicks is a photographer’s model from Skokie. On Tuesday, she was riding the Red Line into the city. Her train was approaching the Jarvis stop when it happened.

“A thug on the train snatched my iPhone 5,” she says simply.

The thief was smart. He acted at just the right moment, just before the doors would open and give him a path to his get away.

Jennifer and another passenger tried to hold him back and scuffled with the thief but finally let him go.

She says ”If someone’s bold enough to snatch your possession, you know, do they have a gun? Do they have a knife? What else are they willing to do?”

It turns out, police say, most snatch and grab crimes occur just before the train comes to a stop and the doors open. That’s when riders should be most alert.

Sgt. Tom Osika of the Chicago Police Department’s Transit Unit puts it this way. “The offender knows that they can duck out of the train quickly and by the time you can get up and go after them, the door is now probably closed. They’ve made their escape.”

“I got straight on Facebook and let people know this is real,” Jennifer Wicks says. “You see it on TV. It happened to me, it can happen to you.”

Although CTA on-train robberies are down from 498 during the first six months of last year to 440 this year, they’re still happening every day. A little caution during those dangerous moments can keep riders from becoming victims.

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