LYNN – Karl Reynolds took a 90-minute cardiopulmonary resuscitation course and said he is ready if a fellow commuter rail rider experiences a medical emergency.Ed Finn received medical training in the Air Force and recalled the day it took four or five minutes for commuter rail employees to respond to a medical problem aboard a Boston-bound train. Even as passengers like Finn and Reynolds stand ready to respond to an onboard emergency, the Massachusetts Bay Transportation Authority is stepping up its ability to respond to medical problems.The T is equipping its 84 commuter rail trains serving Greater Boston with automated external defibrillators with the goal of outfitting every train by the end of the spring. The devices analyze heart rhythms and provide information on how to administer a jolt to the heart of a victim of cardiac arrest.This type of medical emergency kills 325,000 people in the United States every year.”We want our customers whether traveling 50 miles to Fitchburg, or 44 miles to Worcester – to feel relaxed, stress free and confident that we are tuned in to their needs and are committed to providing premiere customer service,” MBTA General Manager Daniel Grabauskas said.Commuter rail conductors and assistant conductors will receive four hours of CPR and defibrillator training so they can respond to adults as well as children experiencing medical problems.Zinnia Lewis wants to see bus drivers trained in medical emergency response. Floris Bailey said people often do not appreciate the importance of being able to respond to a medical emergency until they are forced to take action.”Everyone should learn how to do it,” she said.