Compact Snowpiercer Engine
Snowpiercer, the eternal engine, the sacred engine etc, once an railiner, now an ark for what's left of the human race. The engine is powered (For now) by two steam engines, driving the large twelve powerful driving wheels. Assigned to the task of harboring the last humanity comes down to three people. The Locomotive Engineer, responsable for Locomotive operations outside drive the engine, (though cover for the engineer if they are ill.) and unsureing that the engine is running at max effort. Next, The Coupler Man, assigned for operating the front coupler, however with the new ice age, the CM manly helps in mantaining the engine. And last, The Driver, (AKA Mr Wilford/Insert Weathly CEO here) with the job of driving and leading the train through the eternal winter.
How to start (and drive) the Perpetual Motion Machine,
Step One: fill both fireboxes with coal.
Step Two: prepare the engine for engine start.
Step Three: Wait until both boiler pressures are at over 100.
Step Four: Slowly increase throttle.