The Chicago-area's commuter rail agency is installing hundreds of portable, easy-to-use defibrillators on all of its trains.
Metra is only the second major metropolitan transit agency in the country to make the machines available for use in the event a passenger suffers a cardiac arrest.
In 2009, Massachusetts Bay Transportation Authority commuter trains became the first in the U.S. to be equipped with automated external defibrillators.
Defibrillators are required on airliners and in public places such as sports stadiums. But cost and lack of training have prevented a greater proliferation.
A $536,000 grant from the Regional Transportation Authority is helping to pay for Metra's defibrillators.
Metra Chairman Brad O'Halloran says he hopes staff will never have to use the machines but that it's important to make them available if needed.