The film's story takes place aboard an out-of-control train.

Barker intended the film to be a parable about life, and how the ruling class tries in vain to insulate itself from the fate suffered by the lower classes:[8] The metaphor of this film is that, whether you notice the jeopardy or not, everybody is trapped on this track, and we’re all going to the same place,” Barker explains.

But a lot of people I know [have] that kind of disbelief that anything can shake their normal day-to-day life,” he says.

The entire film was made with hand-drawn animation, with the exception of some more visually complex scenes: I brought on Frantic Films early on in the production to just do a couple of shots where the train is doing a three-dimensional action.

It's one thing when things are moving past the sides of the camera, everything's moving more quickly, but that end point, the perspective point where its are barely moving from frame to frame - that would have been just horrible, trying to animate that.