Was It a Mechanical or a Sabotage?

The NTSB says there was an alert but it is not known if it came from the hot box detector in Salem or the next one down the track 20 miles away. In front of that plant is a hot box detector which scans the temperature of the axles as the train passes and sounds an alert if they're overheated. If the alert wasn't triggered when the train passed Salem, why not? I'm just giving you both sides. It's the right thing to do. We'll have more facts and we're going to get them for you here.