The simplest description of the titular Iron Council, from China Mieville’s novel of the same name, is a runaway train city. As a transcontinental railroad slowly extends out from the steampunk megacity of New Crobuzon, the working conditions along the railroad become so dire that a union of prostitutes and tracklayers, prisoners that have been mutated and mutilated for punishment, steal the mining train to seek a new life in uncharted territory. The massive train runs away with its own tracks, which are dug up and re-laid perpetually as the train slowly but constantly moves forward. For several decades it slowly rides its own rails out of reach of the city and system that birthed it. In the safety of the unknown, the Iron Council slowly moves through the fertile fields that sustain it.
When a runaway train brings along the runaway tracks, it’s inherently limited by that pre-existing infrastructure. What follows is an attempt to extract the governing geometry of a fictional anarchist railroad city.
The Iron Council is mostly described through its aesthetics: The train is pulled by four engines with diamond-profile smoke stacks; the front engine has a cow catcher and is decorated with the heads of hunted beasts and defeated foes; there is a gun-tower car, a laboratory car, a multi-level sleeping car, and a car that is transformed into a wheeled amoeba by the fantasy equivalent of radiation1. The defining dimensions of this train (gauge, wheel configuration and car length) are not described but there are certain descriptions that provide clues to mapping out the Iron Council’s possible paths.
The first physical limitation of the Iron Council’s movement is it’s track radius. The greatest limitation to a trains’ turning radii is cant (the tilt, perpendicular to the direction of travel). However, as the Iron Council moves with the construction of its track, “[creeping] forward with the tiny turns of its wheels,” its’ speeds are implied to be so slow that cant is nonexistent2. At these speeds, the determining variable for turning radii is the lateral travel of the locomotive’s axles. The only size description of the Iron Council’s locomotive is that it is “pushed and pulled by four hulks”, so we can make assumptions using the characteristics of a hulking, historical steam locomotive: the Union Pacific Big Boy, 132 ft. long (including the tender/coal car) with a 4-8-8-4 wheel configuration3. Because the lateral travel of the US drive wheel has a limit of 3/4”4, the turning radius is 648 ft., safely larger than Norfolk Southern’s minimum recommended long-car radius of 574 ft5.
The degree of a possible turn is limited by the overall length of the train. In the text, the Iron Council is described as being “a mile long track stretch”6. This limits the train to a 230 degree radius along a tight turn; anything greater would see the train collide with itself.
With these basic limits established, the possible path of the City can be drawn. Since the Iron Council reuses its tracks indefinitely, there is no endless stretch of rail behind it except for stray rails and ties. The resulting illustrations show the whole of it’s “trackprints” and route, as differentiating between past and currents paths on a drawing of about 16 square miles at the correct scale would be illegible.
The resulting Iron Council is a small strip of focused activity. It can roam freely within its refuge, but due to its mechanical constraints and linear form, it has only a limited arsenal of sweeping moves it can take to get where it is going.