NTSB is basically handing the plaintiffs their case on a platter. There was no law requiring PTC and no standardized system (both are being addressed now by FRA and Congressional compulsion, but the standardization isn't quite ready yet) but NTSB says the magic system would have prevented Placentia (how, precisely, given the timing involved and the fact that the nut's SUV wouldn't have been equipped with a transponder?) and Chatsworth (a better argument there, but still not perfect) and Metrolink didn't do it immediately with still-experimental systems and with equipped/non-equipped traffic on the same lines (a bad move, if it had been done), so the Chatsworth wreck is Metrolink's fault not the texting/chatting engineer who didn't notice a switch set against him regardless of the alleged state of the signal and the prior signals. In the real world, whether fair or not, this would and should be the end of Metrolink as we know it. Railroads and especially commuter railroads are not completely in the real world, of course. Neither, methinks, is the NTSB, and neither is the lawsuit/liability process that this all feeds into.