The Case IH Quadtrac tractor is built in Steiger's Fargo, North Dakota, USA factory by Case IH. It originally had a 360hp Cummins engine, but subsequent updates raised it to over 650hp. The Quadtrac is now one of the most expensive tractors ever. The largest Quadtrac model produces 692hp, the most powerful tractor in production.
For more information, see Case IH Steiger.
The Quadtrac was designed to compete with the highly successful Caterpillar Challenger. To save the costs of developing a tractor from scratch, they instead opted to modify their 9370 articulated tractor. They began production from around 1997. Case still produces the Quadtrac to this day, with around four models available. Most modern Quadtracs feature 400 to 680hp.