Free Traction City by Philip Reeve

1
    These were mountains once. In Ancient times men knew them as the Alps. But bad things have happened to them in the centuries since: earthstorms and ice ages; a Slow Bomb strike in the Sixty Minute War. Now they are the Shattercountry, a steep land of rubble riven by clefts and rat-runs where the mining towns crawl, gnawing ore out of stumps that once were mighty peaks.
    But tonight the passes are deserted. The mining towns have fled. The Shatterlands shiver at the coming of a new disaster. Up from the lowlands, engines roaring, smokestacks spewing thunderheads, a city is advancing. Banks of gigantic caterpillar tracks grind the ground to gravel as it goes. Above them, stacked in seven tiers like the layers of a wedding cake, the body of the city towers; factories and work-yards on the largest, lowest level, shops and houses on the ones above. The higher tiers are smaller and have parks about their edges, though the wild winds of the Shatterlands have stripped the trees of leaves. On the tiny topmost tier, among the council offices and politicians’ palaces, an ancient temple to a forgotten god has been rebuilt, in honour of the city’s past. Even the wretched Anti-Tractionists, watching from their hilltop hovels as it lumbers by, know the famous dome of St Paul’s Cathedral. It tells them that this juggernaut is not just any city; this is London, first and greatest of all the Traction Cities of the earth.
    For centuries now it has dominated the Great Hunting Ground that lies north of here, devouring smaller, slower towns to feed its endless need for fuel and raw material. Now, for the first time, its ruling council has decided to take it across the high passes to hunt upon the plains of Italia.
    Smiff, ten years old and creeping catlike through the city’s bowels, knows none of this. The Council might as well be gods to him, they live so high above the dank and rusty streets he knows. On the bits of Base Tier where he makes his living there are some worrying-looking rust holes in the deck plates, and you can look down through them sometimes and see the great wheels turning and the ground sliding by far below. But Smiff never knows which bit of ground it is, or what part of the wide world his city is hunting in. All he knows this evening is that London is climbing, and has been climbing for a long while. The roar from the engines is louder and harsher than usual; streets that are usually flat have developed a steep slope; the heat is immense.
    One good thing about living in the chassis of a Traction City is this: the stuff that rich folk drop on tiers above comes down to you. Maybe a lady on Tier One feels the clasp of her necklace break while she’s taking the air in Circle Park. Before she can stop it it’s slithered through one of the gratings in the deck that lets light and air down to the tier below. It lands in the busy streets of Bloomsbury, where the wheels of one of those new electric cars clip it and send it down another grating to Tier Three. And slowly, if Smiff’s lucky and no sharp-eyed Smiff-like person on the higher levels spots it, the ceaseless movements of the city shake it down from level to level, through grating after grating, until lands at last where all things must, on the grimy deck plates of Base Tier.
    At least, that’s what Smiff is hoping as he scurries towards Mortlake this evening. It’s been a long time since he found anything better than a bent fork, but there are good gratings in the roof of Mortlake, aligned with other gratings right up through the city. All sorts of strange stuff comes rattling down to Mortlake.
    Â 
    Mortlake is an old industrial section, part of a huge complex called the Wombs, where, back in the glory days, London used to build whole suburbs for itself, refitting towns it caught and sending them off covered in bunting and civic pride, carrying some of London’s excess population away with them. But it’s been sixty years