Went back and forth on this one. At first I really liked it. Then, after the titular train wreck, I wanted to punch half the characters (not the actors) for their mindless panic and poor choices. A bit later, during the third act, I started to "get" what the story was going for. One thing that helps a lot is to re-filter what you've watched with the revelations near the end. Admittedly, I laughed at moments that I wasn't supposed to, but honestly, if you think of this as an overlong Twilight Zone ep, it's really not that bad. Kinda good, after a fashion.
At points in the film, I couldn't wait for it to be over, but ultimately, I have to admit I enjoyed myself, and don't regret watching it. Whether that's a dig or a backhanded compliment I dunno. Had I read this as, say, a short story, I bet it would have been excellent, and the cast were decent actors for the most part (the kid certainly has a future in front of a camera), so I'm not entirely sure what caused it not to fully "gel." Maybe it was the anachronisms (can't elaborate without spoiling things), or perhaps the overwhelming sense that a twist is imminent from early on.