Detailed text transcripts for TV channel - CNN - 20171219:05:47:00
Control. can you explain exactly what that is and how that might have been able to make a difference in this crash? >> so positive train control has been around for decades. this is not new technology. and in fact, in 2008, after 25 people were killed in a metrolink crash in southern california, congress required that all passenger lines and high hazmat lines install positive train control by 2015. and so they gave the railroad seven years to do it. congress pushed that deadline back when it became evident that many of the railroads weren't going to make it and so the concern from a safety per...