The push for more horsepower shows no sign of slowing, judging by the latest tractor launches due to take place at this November’s Agritechnica show.

Case-IH started the ball rolling with its announcement in August of a bigger-than-ever Quadtrac 620 (see Top 10 tractors below) with a rated power of 628hp and a barnstorming max power figure of 692hp.

Now Challenger has revealed that its latest rubber-tracked crawler – the MT875E – has become the company’s most powerful tracked tractor ever. It churns out a rated output of 590hp and a maximum power of 640hp, 30hp more than the current MT875C.

It’s also reckoned to be the first time a 12 cylinder engine has been fitted to a tracked tractor. In this case it’s an Agco Sisu powerplant with 16,800cc under its belt and both SCR and water-cooled EGR.

Big tractors are obviously specialist machines for the very biggest farmers and contractors. About 500 Challengers are sold in Europe each year, says the company, and the UK is the biggest market with some 100 sold a year. Italy, Russia and South Africa are also good markets.

All mainstream manufacturers are under pressure to raise their power outputs to meet the demand from farmers and contractors. Deutz-Fahr, for instance, has up until now been happy to occupy the centre ground in horsepower terms.

But it announced last week that it will be selling two new ranges called the 9 and 11 Series that will top out at 340hp and 440hp respectively. That’s a big jump on the 263hp its current biggest tractors musters.

Power comes from a 12.8 litre, 6-cylinder Mercedes engine and ABS braking is expected to feature. The 11 Series is expected to go on sale at the end of 2015 and has other big-tractor features like a 12t rear lift

Meanwhile the biggest model in the latest generation of Valtra S series – the S374 – gets a power boost to take it to 400hp. That’s thanks to twin turbos and an electronically adjustable wastegate. Lift capacity is a meaty 12t on the rear and five on the front and the AutoComfort cab suspension automatically alters the suspension according to the conditions. The new models are expected to go on sale in spring 2014.

How much more powerful can tractors get? A lot, say manufacturers. If the demand is there they’re happy to keep upsizing.