CHICAGO (CBS) — Metra is installing new life-saving defibrillators on its trains.

WBBM Newsradio’s Mike Krauser reports officials demonstrated the use of the automated external defibrillators on a dummy Thursday morning at Millennium Station.

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Metra Board Chairman Brad O’Halloran said the portable defibrillators will be installed on about 300 Metra train cars.

“We are adding something to our trains that, hopefully, none of us ever have to use,” he said.

Anyone can use one of the AEDs, which won’t shock a patient unless it’s necessary.

Gov. Pat Quinn said it’s a great step forward.

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“There’s a passage in scripture, and it says ‘if you save one life, you save the whole world,’” Quinn said.

The defibrillators actually talk users through the process of using the devices to monitor a person’s heart rhythm, and applying a shock to restore normal heart rhythm.

Dr. Amer Aldeen, an emergency physician at Northwestern Memorial Hospital, said “even before professional medical personnel arrive, bystanders can save the lives of their fellow citizens. Performing chest compressions and using an AED can almost triple survival outcomes from sudden cardiac arrest.”

Tracy Trimbull, a Naperville resident, has twice used an AED at the health club where she works.

“They tell you when to put the pads on, they tell you whether to push the button or not, and you can’t hurt anybody,” she said. “Anybody can be a hero here, absolutely.”

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The Regional Transportation Authority was covering the $700,000 cost of the defibrillators.