Yes, the driver doesn't want to make any statement if not to the judge. It seems he has been advised to act that way, as what he says can be used against it. Right now almost everything points him as the one who has the fault... and I suppose it's true, but I prefer to wait. Some years ago it was a terrible accident in the metro in Valencia. A lot of people died, and all the fault was said to be from the driver (who died in the accident). Now we know it's not the truth! The politicians and "great bosses" were interested in the investigation went not further, as there were more responsabilities there, political ones. Thas has been a hot subject just before the train accident, because it has been asked the investigation to be reopened, but there are too many interests not to... So, although I suppose it's mainly the driver's fault, I don't want to judge him, yet.
About the security system, it was supposed to be two: long before the rail bending, if a too fast train is detected, a warning appears to the driver, and he must aknowledge it and reduce speed. It seems the warning worked, but for some reason, the driver didn't reduce. Apart from that, there was a mechanism to force the train to brake, but I've read somewhere it only worked if the train was at more than 200 km/h (and this one "only" was at 190!). I've also read that this rail has several zones, some of high speed, and some old ones. At the moment of constructing the line, there were zones very populated, so they didn't expropiate those zones to avoid any problemes, and made a "high speed... now low speed... now high speed again" track. The tracks were very old there, from Fraco's time! Of course, the zone of the accident is an old and close bending track after a long new straight-for-a-lot-of-kilometers zone. The train could go to 200 or more and break 4 km before the curve, to 80-90 km/h. For some reason, it didn't.
It's also said that the train was arriving 5 minutes late... what could have compelled the driver to go faster. Faster... but 190 instead of 90?
And there's a second driver: how's that the second one didn't pulled the brakes if the first one didn't? There are too many questions, and, sadly, I'm not sure they'll be answered. I know too much what happens in that kind of accident. I don't know if they are, but if any politician has any responsability (lack of money, interests in avoiding problems when the line was made, a dangerous bending because of saving money...), nothing will really happen to them. No one will have to resign, no one will go to court (and if they do, they will be declared innocent).
I'm sorry for my pessimism... but lately I can't see anything good in great politicians...
