Nobody wants a runaway train. They have caused horrific damage around the globe, both physically and psychologically. Though precautions and rules have been established to prevent such runaways, they still happen. They still cause damage. They still cause trauma.

They still cause atrocities.

One cold night, a big and powerful steam locomotive dragging a long and heavy train of ore is left in a siding at the top of a mountain so the crew can rest.

Unknown to them, a boiler leak is letting steam pressure drop. The steam pressure dropping means the air compressor supplies less and less air to the brakes. The air pressure dropping means the brakes become less and less effective.

With not a single soul to watch - except for a fiery Pegasus - , the train begins to move downhill, completely unattended, threatening to destroy the small town of Detrot.