Ultimately unsatisfying. Here's a quick outline:

* Trains are safe, but they aren't safe enough.
* Chatsworth and Pilly crashes >> must have PTC; then mentioning a bit later that the NEC has it. Leaving out that it was still under construction at the Philly crash site at the time.
* Some simulator rides with PTC.
* B-roll of Pueblo crash tests, repeated several times.
* Interesting small bit about seat and table redesign - doesn't make the crash-resistant seats used on LA Metrolink any more comfortable or less claustrophobic.
* Oil Trains! Footage of big booms and some fairly terrifying footage from Lac Megantic. Followed by some discussion of improved procedures and tank cars.
* yadda yadda...but taking people out of the loop isn't enough (infrastructure & equipment failures)
* Risk on trains way below risk on highways.
* Trains are safe, but they aren't safe enough.

Nova has definitely declined in attractiveness as a science and technology show over the last few years. But to do this better (not necessarily right) probably would have taken multiple episodes, as with the air travel show that followed it on my local station.