I have not seen the movie yet (I'm planning to) but from the commercial I can tell you that when a train hits a car it doesn't bounce in the other direction. The "train" was actually a big rig mock-up.
Note the tires in this picture:
http://railpictures.net/viewphoto.php?id=298478&nseq=1
Here is one of it during the shoot:
http://railpictures.net/viewphoto.php?id=298049&nseq=2