A Burlington Northern freight engineer who ran past two warning signals most likely caused the head-on crash with a Metrolink commuter train that killed two and injured hundreds of others, according to preliminary findings released by federal investigators. National Transportation Safety Board officials, having ruled out brake or other mechanical failure, are focusing on the freight operator reported The Los Angeles Times. Investigators said the freight engineer appeared to ignore or miss a yellow signal light approximately two miles from the collision site in Placentia, Calif. A minute and a half later, the 67-car freight train was signaled by a red rail light to stop, but the train was traveling too fast to prevent it from slamming into the Metrolink cars, even after applying the emergency brakes, said the paper.