Editing Snowpiercer (section)

===Utility Cars and the Sub-Train===
Numerous Carriages are shown to be preceded by intermediary Utility and Battery Cars. Those cars are necessary to maintain life support systems (water, electricity, temperature, air quality...) all along the train. Battery Cars mainly house power banks to accumulate power as the train travels. At least 37 Battery Cars were offline after the civil war.

Each car has two [[Sub-Train]] platforms underneath its main deck. The platforms, only accessible from Utility and Battery Cars, is where the bogie motors help maintain the speed of the train. A cable car transportation system runs all along the tunnel of this platform and transports goods and people from section to section. Due to the borders between Third, Second, and First Class, the Sub-Train might actually be divided into three closed-loop subsystems for operating reasons (it is faster to operate small distance trips).