Agreed. The physical impossibility of the train is what got to me(where did all these soldiers come from? did they march through the nightclub and kindergarden wonderland cars?).

That said, it is very well produced and if you can set aside the technology aspect of it I would say it's among the better sci-fi movies in recent memory.

Essentially all fiction requires some degree of "suspension of disbelief." We all have different tolerances both in general and in specific genres where we might have more knowledge than the average person. Or we just have trouble buying a particular premise. Certainly there are films I love even though I know they depend on a setting or assumptions that are pure BS. And there are other films or TV shows that I otherwise really like but just can't really get past some particular aspect.

Actually, I kind of liked that idea, that they did march through the nightclub, etc. I mean, the rest of the movie was rather trite (though not the worst I've encountered), trying to imagine life on the train was one of the best parts for me.

I was more bothered by the silly melodrama you got at a number of points, personally ("I know that <spoilers> taste best!"). It did have some really great scenes, though. The schoolcar scene was top notch. And it was quite impressive visually.