Set seven years after the world has become a frozen wasteland, Snowpiercer centers on the remnants of humanity, who inhabit a gigantic, perpetually-moving train that circles the globe. Class warfare, social injustice and the politics of survival are questioned in this riveting television adaptation. Written by TNTDrama
It suffers from two basic problems: 1) It's been made into a detective show, and 2) the world doesn't work.
The problem with #1 is that the train's operators assumed everyone would play nice, and so got rid of any current technology that would have helped. This of course means that they need to go grab someone from the poor section to solve the case.
With #2, it just doesn't work. The show is just too dependent on its allegory and is so hooked into it that they didn't bother asking how it worked. They needed someone to make the ecology work, and personally I would have found a way to make the people in the last car work for what they get.
In all honesty, there are just too many issues on way too many levels for this too work....