In the classic drama's 150th episode, a multi-car train accident scrambles the ER and Drs. Kovac (Goran Visnjic), Carter (Noah Wyle) and Corday (Alex Kingston) are overwhelmed by the carnage at the site as they work to save an impaled mother, her young son and a trapped firefighter -- until the pregnant Corday begins to suffer painful contractions. Back at County, Dr. Benton (Eriq La Salle) tries to salvage a victim with a shredded aorta and even helps Carter with a tricky amputation over the phone, all of which leaves an observing med school applicant wide-eyed. Meanwhile, the bloody mayhem prompts Kovac to recall the harrowing loss of his own family and he confronts his torment with the terminally ill Bishop Stewart (Oscar-nominated guest star James Cromwell, "Babe"). Away from the hospital, Dr. Greene (Anthony Edwards) is summoned to the emergency from his humiliating competency testing.