The Explorers (Snowpiercer, #2-3)

Snowpiercer Vol.2 is the second volume of the enthralling and thought-provoking post-apocalyptic graphic novel series that inspired the critically acclaimed movie starring Chris Evans (Captain America/Fantastic Four). Originally published in French, this marks the first time that Snowpiercer will be available in English.
 
In a harsh, uncompromisingly cold future where Earth has succumbed to treacherously low temperatures, the last remaining members of humanity travel on a train known as Snowpiercer while the outside world remains encased in ice.

The occupants aboard the Snowpiercer believed themselves to be the last humans alive, yet they soon learn that they are not alone. There is another train that could potentially spell destruction for the passengers of the Snowpiercer as it carves a trail through the endlessly freezing terrain. 

This second train houses a small band of people that are willing to brave the relentless cold in search of the truth and discover what is left of the world by any means necessary.