Never mind if the ID is real or fake IMHO there is no Do Not Train (??) List as there is a Do Not Fly for air travel, not that that list has stopped anyone that was a real threat. Furthermore when the ID is checked it is just matched with the name on the ticket. This ID checking on the train also assumes that whoever is going to do harm to the train is going to leave the train before the "event' happens. In most of the recent events the terrorist are killed also. Small comfort to have a name earlier rather than later. Finally if you are going to do harm to a train it would seem that forcing a derailment at high-speed would be easier and more damaging.