Vigilus - Ork Scrap Cities: The Ork settlements and junkyards that sprang up in the planet's wilderness were known to all as "Scrap Cities." From these came tides of barbaric xenos and an endless parade of war engines.In the year 1.192 post VCM.M41, a vast agglomeration of Ork voidships -- each of which had uncharacteristically massive and powerful engines -- ploughed through the hastily assembled Imperial cordon sent to blockade it and made straight for the surface of Vigilus. Most of the ships aimed not for the metropolises of the hivesprawls, but for the regions of wilderness between them that would act as ideal staging posts for the invasion.The vector of the Ork invasion was straightforward enough -- most of their spacecraft simply bulled their way through the stratosphere, pulling up over the last few Terran miles and angling their landing so they did not dash themselves to pieces on the wasteland dunes. It was a haphazard invasion tactic, that much was sure, but it worked.Some Greenskin ships came apart in fiery arcs of destruction, spinning end-over-end as they flung burning scrap metal in all directions. The shock waves from these crashes rolled out across the deserts, battering far-flung monitoring stations and hammering refinery pipelines with each landing. Huge dust clouds were kicked up into the skies like atomic blasts, turning the air hazy for solar days.The survivors were numerous enough to shrug off their early losses and repurpose virtually all of the scrap metal provided by their unfortunate comrades, using it to build immense, if ramshackle, fortresses.Some ships, protected by powerful energy shields, made the landing all but intact. Their force-field generators were intact too -- projecting a kind of matterphobic dome known as a "bubble field." Adapted to protect the scrap fortresses, they remained functional throughout the War of Beasts, repelling many of the Imperial sorties sent against them.These shields, like the fortifications they guarded, were testament to the strange, innate genius of the Ork Mekaniaks that built them.Speedlord Krooldakka and his warlords were savvy enough to realise that to attack the cityscapes head-on from orbit would invite a vast amount of flak and defence laser fire -- and that even if they somehow made a safe landing amongst the dizzying hive spires, arches and statues of the cityscapes, they would almost certainly be surrounded and picked apart before they could muster a cogent invasion force.Some of the Ork war leaders simply intuited that to invade via the wastelands would lend them a better chance of victory. Others wanted a chance to race their favourite wagons around their new home for a while before getting really stuck in -- after Terran years of being cooped up in the confines of a spacecraft, the scouring winds and open terrain of the Vigilant desert were a welcome prospect.The first wave of invaders, upon finding they could not get past the Bastion force field networks, built shanty-styleencampments around their crash-landed voidships. They set to work conquering the landscapes around them, attacking Imperial convoys wherever they tried to cross the wastes. As these running battles gathered pace, the resultant flotilla of Ork vehicles became known as the SPEEDWAAAGH!.