Train accident analysis

In the wake of the recent Washington, DC commuter train collision, Popular Mechanics has come out with an article that lists ten lessons learned from various train accidents over the years.  One of the accidents was a CTA el train derailment where the cars came off the elevated tracks in the Loop.  The lesson learned from that was the train operators were not allowed to override signals without clearance from central control.

From the news stories coming out of the DC train derailment, it appears that the lesson to be learned from that equipment must be properly maintained and upgraded as needed to assure rider safety.  It sounds like an obvious principle, but apparently one that hard to be reinforced through tragedy.