Probing Metrolink Crash

As federal safety investigators probe the Metrolink train crash that killed 25 in Chatsworth, a key question is whether the engineer obeyed track side warning signals. The engineer, who was killed in the crash, ran a red signal before slamming into a Union Pacific freight train on a single line of shared track, according to the National Transportation Safety Board. The NTSB probe is ongoing into the worst train accident in modern California history.