Automation plays a very interesting role in the plot of Snowpiercer. Because the train is designed to work forever, most of the functions are partially automated. For example, the cockroach protein bars that the tail-enders eat are produced by one single person who simply keeps the machine running and pulls the bars off when they're done. But on the other hand, you have the heart of the train, the perpetual engine, which would normally be the optimore of automation but cannot run without human children inside it to replace parts that have worn over time. This wouldn't be an issue in a normal society but because the train is completely isolated, it can’t get any new parts. As time goes on, the machines become less valuable and the humans the opposite. It’s a very interesting contrast to how things work in a system where new resources can be introduced.