Forktresses are a very notable piece of Ork technology. They are generally massive, walking fortresses and siege machines that were mass produced at the height of the ork civilization's existence, and were highly feared across the globe for their incredible firepower and immense size.
Most forktresses were commisioned directly by Warlord Gorgutz 'Ead 'Unter, and are something of a trademark of his rule over the orks. Since his reign, they ceased production altogether and were instead replaced by cheaper, smaller machines. It has been said that the continent of Orsinium is walked upon by thousands of these walking, metal monstrosities. However, since the UNSC's nuclear strike on the continent, it is theorized that all remaining forktresses have been destroyed. However, this is most likely not the case.
The greatest, strongest, and most massive of all the forktresses was the Warlord's personal carrier, the Big Bugger.
Construction and Usage
The Forktresses (ork fortresses) were some of the largest engineering projects in all the race's history. Up to tens of thousands of ork mekboys and peons would all work on a single forktress at a time. These engineers and builders would work a project (a single forktress), and this project would be overseen by a Big Mek, the highest ranking ork mekboy in a klan, a usually large and powerful ork, to say nothing of his engineering prowess. Through their incredible brutality, leadership skills, and desire to build the best forktress of any other, the klan Big Meks dished out up to 3 half mile long forktresses a year. Counting all the ork klans on Orsinium, over 400 forktresses were produced a year in total. They each are essentially stacks and plates of thick metal sheets, all made mobile by hundreds of large, powerful legs.
Forktresses, due to their size, power, and fuel consumption, required huge amounts of oil to power daily. Thankfully, due to Orsinium's abundance in crude oil, they were more than able to meet their oil needs. In fact, the ork meks devised another system of oil harvesting to boost efficiency. They turned their forktresses partially into oil refineries. With special mechanisms built into the massive machine, they are able to drill and harvest millions of gallons of oil to be used for their own needs, or for sale in the market.
In addition to being smoke-belching oil refineries, forktresses were also designed to be both walking cities and siege weapons. Able to house (at maximum) half a million orks each, forktresses could carry entire WAAAGH!s of orks on wars. Outfitted with bunks, barracks, food stations, armories, and factories, a single forktress could accomodate a WAAAGH strong enough to take a large island.
Forktresses were also created to lay siege to cities, territories, or targets. Equipped with huge accelerator cannons, heavy chainguns, and mortars, a siege forktress is truly something to be feared. Their guns unleash a storm of bullets and projectiles that can literally obliterate anything in its path, leaving just a smoking, flaming crater where its target once was. Warlord Grogutz's personal forktress, the Big Bugger, was powerful enough to flatten an entire city alone in a matter of half an hour. Truly, Gorgutz had nothing less than complete annihilation in mind when he commisioned the forktress projects.
After the UNSC's obliteration of most of Orsinium, the Earth alliances theorized that all forktresses were destroyed in the nuclear strike. However, a few of them survived and were rediscovered by ork survivors Like the Black Hand Klan, and are possibly being analyzed for purposes of recreating them.