2.5 rounded up. A fun YA adventure, but having it from Will's POV negated any awesomeness the single (1! No other females were main or secondary characters, nor did any have more than a bit part in small scenes) female character may have had. It's a good yarn for the age group it's aimed at.

The train's pretty cool too, though I could only think of Snowpiercer (graphic novel turned film with the same premise, but dystopian/post-apocalyptic) as I read the descriptions of the various cars and class separation.