I don't quite understand how, but this train has self sustaining power and as long as it keeps moving it generates energy for it to keep moving and sustaining life in the train.

Nuclear power generated by small reactors like on submarines could keep it moving for a very long time as in decades. The requirement to move would only make sense if snow were used as a coolant for the reactor. I don't know how much water per unit of time does it really take to cool the reactor of a nuclear submarine.

In any case, this is a type of road movie.