Snowpiercer

The train in Snowpiercer is both transport and the entire functioning society its passengers have left. Outside is a frozen world; inside, access to space, food and authority depends heavily on where someone is allowed to stand.

Daveed Diggs and Jennifer Connelly give the opening conflict different perspectives on keeping that society alive. A system can be technically necessary and still be organised in ways that benefit some people far more than others. The train's practical constraints make those arguments difficult to escape.

The television version expands well beyond the compact movement of the film. That gives relationships time, but also introduces uneven plotting and repeated contests for control. The contained setting remains the more reliable source of interest.

It is a worthwhile speculative drama if you enjoy a society whose physical design exposes its disputes. Silo is a more controlled version of that attraction; Snowpiercer is noisier, more openly confrontational and often carried by the people trying to explain why the train must keep running.