I won't repeat the vast list of technical errors and impossibilities that the previous commentators made, I think we all spotted them for ourselves. My comment is in a different direction.
I frequently have issues with commentators who concentrate on technical errors in movies. I think that often they have missed the point. In this movie, however, such commentary is entirely relevant. Here, the entire movie is about (correction, is SUPPOSED to be about) the "technics" of a modern computerised train gone wrong. Thus, in my opinion, in a movie like this, the movie makers have an obligation (to their own credibility, if nothing else) to get the technical details right, because in theory, that's what their movie is trying to show! If they don't, they suffer the consequences: as so many of the other commentators said, the movie becomes a spoof of itself.
Also, and I'm a bit surprised that no-one else has picked up this point, I would have thought that by 1999 we would have gotten past the cliche of "infallible computer fails". Or was this some kind of twisted pre-Y2K hype?