> In much of Asia and Europe, engineers are protected by a technology known in the United States as positive train control, or P.T.C...Amtrak has been working on its own in-house version of P.T.C., called the Advanced Civil Speed Enforcement System, or Acses, for almost a decade. But owing to insufficient funding and a row with the F.C.C., which Amtrak said had been slow to approve the use of the requisite radio bandwidth, its actual implementation has been piecemeal. At the time of the accident, large portions of the Northeast Corridor, including Frankford Junction, were not online. Practically speaking, that meant engineers were working with no safety net.
Near the end of the story:
> In late May, Joseph Boardman, Amtrak’s C.E.O. and president, promised that the installation of P.T.C. on the Northeast Corridor would be completed by the end of 2015, a pledge he has kept: Today, the system is active on all routes, with the exception of substantial stretches of track owned by the State of Connecticut. (A spokesman for the Connecticut Department of Transportation said it hoped to have P.T.C. installed on all state-owned track by 2018.)
A technology that had stalled for a decade -- for ostensibly "hard" and "complicated" reasons -- is completed within months after a disaster. Just goes to show how much tragedy and politics has an effect on implementation and prioritization of engineering improvements.