Training - the crews need training. And a system that works, but that's a technical matter. How's Metrolink doing with it in LA?

I've seen several articles in the train and tech press about PTC - both as it is and as it could be. The basic answer is: as presently being implemented, it should do little or nothing for operational flexibility. It's essentially an overlay on existing signals and other train control (mainly, authority) systems that improves safety under certain circumstances (mainly, potential train-on-train wrecks).

There's plenty of speculation about what PTC *could* do, all the way to (as others have mentioned) eventually supporting driverless trains in combination with many other changes and improvements. None of those those are really here yet, and may not arrive for a long time, at least as part of PTC.