I didn't love "Snowpiercer." But it is a solid action story (once you get past the unbelievable parts) with great production values and good acting.
The storyline: In the year 2014, global warming has created a horrifying situation for the human race. To combat it, we seed the clouds (I guess) with a chemical that will cool the planet down. This isn't all entirely clear but the result is the Earth freezes solid and kills off humanity except for those lucky enough to board a train with an eternal engine that continually circumnavigates the globe. Yeah. Uh huh. That could happen.