Tractor Pulling is known as the world's most powerful motorsport and has been described as a sport in which the unstoppable attempt to pull the immovable. The sport began in the USA when neighbouring farmers competed against each other to see whose horse could pull the heaviest weight. Naturally, with the introduction of technology, tractors took over from horses. Soon farmers were putting higher horsepower engines in their tractors, adding turbochargers, highly tuned fuel pumps, and it wasn't long before multiple engined tractors were introduced. Today it is not uncommon to see "pullers" with 5 v8 engines on board, or 3 v12 aircraft engines that were last seen in World War 2. To those who have never heard of tractor pulling, the sport has advanced considerably from the early days of trying to pull a solid heavy weight as far as possible. Nowadays sophisticated weight transfer machines are used to determine a winner over a 100 metre long track. The weight transfer machine, known as a sledge, looks somewhat similar to a lorry trailer. It is there that the similarity ends. The sledge has wheels at the rear, a long metal plate attached to the ground at the front, and a weighted box which sits over the wheels at the start of the track. Through a series of gears and chains the box moves towards the front of the sledge the further down the track it moves, thus changing the weight from rolling weight to dead weight. The friction between the ground and the plate eventually becomes so much that it pulls the tractor to a stop. The winner is simply the machine that can drag the sledge the furthest!