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Traction Cities are vast metropolises built on tiers that move on gigantic wheels or caterpillar tracks. These cities hunt smaller cities (in order to tear them apart for resources and fuel) which in turn hunt towns which in turn hunt villages and static settlements. This practice is known as Municipal Darwinism, which was a philosophy created by then chief engineer of London, Dr. Gideon Crumb, and is based on the evolutionary theories of the [by-then] ancient philosopher Charles Darwin.


Traction Cities range in size from enormous metropolises (or Urbivores) with populations of millions, to tiny villages and hamlets propelled by small engines or even sails. Airships have become the most common method of transport in this new era, as they are the only practical way to travel between cities - actual heavier-than-air aeroplanes became an extinct technology after the Sixty Minute War (although the technology was rediscovered during either Fever Crumb's time and the war between the Traktionstadtsgesellschaft and Green Storm, it was never mentioned to be used for anything other than fighting aircraft).

Larger cities are usually built on tiers similar to a wedding cake, with the poorer classes living on the lower tiers amongst the tracks and engines, and the higher classes living in mansions and villas at the top of the city. An exception to this is the Ice City Arkangel: as well as being divided into tiers, there is an outer "shell" and an inner area close to the engines. The poorer classes live on the outside of the city, while the rich live on the inside where it is warmer. 

Most cities are urbivorous, and have attachments called "jaws" to catch prey and drag them into the Gut. Here the prey is stripped, melted down and used as fuel, or simply as spare building materials and other salvageable resources, for the predator city's benefit. Its inhabitants of the captured domain, of course, are first safely extracted and integrated into the population of the predator city, or, in less ethical cities, taken as slaves.

Not all cities are predatory, however; some (notably Anchorage and Airhaven) are peaceful and make a living by trading. Smaller towns and hamlets (like Speedwell and Stayns) are also often peaceful and survive by trading or mining. Sometimes smaller towns meet in gatherings to trade known as "trading clusters."

Types of Traction Cities[]


  • Predator - Most Traction Cities are Predators, cities that hunt others for fuel using their jaws
  • Mining - Cities that mine for resources that are to be burned for fuel or are used for trading
  • Scavenger - Smaller towns or suburbs that take from already-captured city wreckage
  • Pack Predators - Often suburbs that work together to bring down larger cities. They also could be working for other cities, in the case of Harrowbarrow and Manchester.
  • Trading - Towns that trade for fuel with others at Trading Clusters
  • Harvesters - cut down trees for fuel, largely extinct due to most trees on the Great Hunting Ground being already cut down by harvesters in the third traction age
  • Fat miners - a mining town that is specialised to scoop up and push along the fatbergs that occasionally wash up on the shores of the hunting ground, the fat is mined down for fuel, illumination, lubrication oil, and rarely nutrition

Raft Cities[]

  • Predator - similar to most traction cities, however the means as to how raft cities hunt or eat other raft cities has not been explored in the books
  • Pack Predators
  • Trading
  • Fishing - So named because of their primary export being fish.
  • Pleasure - Brighton being the chief example, as a pleasure resort and tourist destination for other cities, attracting wealth and culture.


  • Airhaven - Uses gas-filled balloons to stay in the air. Primarily neutral, major trading hub.
  • Experimental - Various experimental towns existed throughout the traction eras, these towns usually had a unique form of locomotion or other unique features over conventional city design.


With aftershocks of the Sixty Minute War still plaguing much of Europe and the north, humanity had settled into a nomadic way of life, trundling around Europe, avoiding major geological unrest by simply moving away from it. Among historians the traction era began with the generally agreed upon date of 1 Traction Era (1 TE) which heralded the reinvention of the Internal combustion engine and likely the steam engine as well. This enabled the nomads to motorise also allowing them to group in bigger numbers and cover more ground, in a movement called the First Traction Boom. Conceptually, the design of the Traction Fortress would have eventually evolved to move entire cities, rather than individual houses as before.

Cutting forward to the mid 400s TE most of Europe had settled geologically and the nomads of Europe settled with it, recolonising cites like London, Paris and Amsterdam (corrupted to Hamsterdam). Only the northern nomadic groups remained, rattling around in the northern snows on the thick ice sheets and northern landmasses. This would not stay this way for long, London had been prior invaded by a nomad group whom stayed in the city called the Scriven. A technologically advanced nomadic group with a penchant for old tech, by all accounts these scriven were mad and dangerous nearly being all killed off in the skinner riots when regular Londoners rebelled. Their final leader through, Auric Goshawk was attempting a solution to this despite its illogical connotations which was a traction city. This proto-city as it were, was going to be a vehicle built by the London masses to carry the last of the scriven to the middle sea allowing them to live their last days in relative peace but only move once, to do this Auric was developing an engine of immense proportions before he died in the aforementioned riots before coming remotely close to realising his dream.

Another nomadic group the Movement eventually caught wind of this story and moved south on London to invade it, taking the city in the Battle of Welcome Break. The movement and its visionary Admiral Nickola Quercus (later Nickolas Quirke) were able to rediscover the engine developed by Goshawk and began to rebuild London as the first traction city. Their reasons for this were generally not known or understood but it is notably down to the rational of moving the city away from encroaching glaciers but also to use as a weapon to crush the other nomad empires. 

London soon proved to work against skeptics and rattled off to war against the nomad alliance facing it, resultantly triggering the Second Traction Boom, a hectic period in which the larger cities in Europe began to try and mobilise themselves in a bid to escape the rampaging London, a doctrine proved sound when the city ate the still mobilising Hamsterdam. The massive resource vacuum this created along with the general eagerness of cities to be the top of the food chain culminated the Wheeled War or Forty Years War, a bloody period when cities clashed resulting in various destructive victories. 

With the second boom underway in Europe the techno-skeptic nation of Zagwa, which had dominion over the African continent and once influenced the south of Europe. Declared a holy war against the new mobile cities in an event called the Zagwan Deluge. The cities valiantly beat back against the deluge allying together to fight the experienced Zagwan military, eventually outflanking and crippling them when Marseille rammed and smashed straight through the pontoon bridge across the pillars of Hercules supplying the invaders.

With Zagwa defeated the Third Traction Boom began with many more smaller towns and cities mobilising, resulting in what is referred to as the Golden Age of traction. It was in this period that Municipal Darwinism was refined at an end of the Deluge and widely adopted, eventually spreading round the globe to the North of Africa, South America, the Indian subcontinent and Australia.

Tractionism didn’t run entirely rampant however, Central Asia had remained a site of relative stability throughout the aftershocks and with the ingress of the motorised nomads various organisations began to block their access into Asia. Eventually culminating in the formalised alliance of Asian nations in the Anti-Traction league and their infamous wall at Batmunkh Gompa. Other pockets of anti-tractionism also exist around the world backed by the ATL or not, namely the Zagwan remnants in eastern and Southern Africa, the Spitzbergen Static in the north and the settlements in the Hundred Islands including Palau Pinang. 

Behind the scenes[]

Traction cities in the books are often modelled or rebuilt after cities in the real world, such as London, Brighton, Anchorage, Paris, or Manchester, and sometimes their names have been slightly modified for comedic effect; for example, Tunbridge Wells has been renamed Tunbridge Wheels and Wolverhampton has become Wolverinehampton. This implies the current traction cities were adapted from older static settlements. Philip Reeve stated that when coming up with the concept he was inspired by how his home town of Brighton was "expanding and swallowing up the smaller towns and villages around".

List of Traction Cities and Towns[]

A complete alphabetical list of the names of known traction settlements can be found here.



  1. The Illustrated World of Mortal Engines (Page 169)