Pioneers: how to drive across Antarctica

The idea to cross Antarctica in winter was conceived in 2008 when Sir Ranulph Fiennes and Dr Mike Stroud came up with a plan to cross the continent - alone and on foot - in the southern winter months. This is something no human being has ever managed before, and is an adventure of mind-boggling physical and mental extremity.

There's just one, small problem: in winter, in Antarctica, the weather is so extreme that there is literally no chance of rescue or aid, should something bad happen. You're on your own. Which meant that, after a long discussion with the Foreign Office, Sir Ranulph was only issued a permit to attempt the crossing unsupported if he could carry all the provisions required for a winter crossing. Which is where we come in.

After gaining the necessary permissions, Sir Ran and his team started to search for a suitable vehicle to pull a mobile landtrain across Antarctica. This would need to carry all the food, medical supplies, science equipment and fuel required to sustain the expedition during a harsh Antarctic winter, when temperatures can drop to as low as -90°C. Which is as difficult as it sounds.

The team looked at various types of machinery from around the globe, and eventually settled on Caterpillar bulldozers. An approach was made to Finning, the world's largest Caterpillar dealership, and after lengthy discussions about which type of machine would be most suitable for the job, it was decided that a pair of Caterpillar D6Ns would be just the thing. The bulldozers themselves were the Goldilocks option: not too big, not too small... just about perfect.

But while these machines are tough in every respect, we couldn't take chances. Knowing where they would be going and what they would be subjected to, the Finning team was tasked with the job of fitting a pair of D6Ns with copious extras. As a result, the two bulldozers - nicknamed Rover and Seeker - are now the only vehicles in the world to have fully customised Antarctic options.

Probably the most important of these are the crevasse arms, which will stop us falling completely into big cracks in the ice. They also double up as crane and attachment points for the ground-penetrating radar, a system to help us figure out where the crevasses are. Quite useful if you don't want to find yourself upside down in a very big hole in the middle of nowhere...

Other extras include hydraulically driven generators, which will supply ‘free' electricity to the living and science accommodation cabooses that will be dragged behind us. There are also heating pads fitted to the engines, transmission and hydraulic tanks, helping to keep the hearts of the Cat D6Ns warm, and roof canopies which can be unfurled to enable repairs in bad weather - a mobile garage, if you like.

The final preparation took place during late 2012, with the Finning team putting in extremely long hours on both machines to get them ready to be shipped down to Antarctica on the SA Agulhas, a special ice-strengthened ship and former polar exploration vessel. Once the Cats were safely on their way, Spencer, I and the rest of the Ice Team flew out to meet the Agulhas in Cape Town, before making our way down to the Antarctic ice shelf where unloading would take place.

We arrived at the head of the Crown Bay inlet the day after we started forcing our way through the floes, but had to wait for another three days while the ice cleared enough for us to crunch our way right up to the Antarctic ice shelf. Once we had managed to secure a position, we had to work quickly. The ship's crane fired up and unloaded one of the sledges and the science caboose - this allowed us to check the condition of the ice until we were given the signal to lift Rover and Seeker from number-two hold and get them onto the ground.

We hadn't been allowed down into the hold to start the engines on the Cats while we were at sea because we were carrying several hundred tonnes of highly explosive fuel in the same hold. But now we could access the area, Spencer and I went down to change a few filters - after their sitting for over a month without being started, we didn't want to take any chances. Then we checked all the oil levels, crossed our fingers and fired up the engines. Soon, the Cats were hooked up to the crane and lifted into the Antarctic sunshine.

As soon as the 'dozers were safely deposited on the ice, I clambered over the bow and down the ladder onto the ice shelf for the first time. And there I was, driving in Antarctica, when suddenly it hit home that although the doors were open and I had the escape hatch, if this thing broke through the ice, it was game over.

Thankfully the surface held firm as I tracked up to safer and thicker ground, where we could start our preparations and put our machines to work for the first time. From then on, daily duties consisted of shuttling fuel and supplies up to the top loading area for storage, until we could move the science and living caboose up the hill to the top staging point. There was a lot to do until we could to be entirely self-sufficient for what might be the next 12 months.

The next morning was busy, and the following day we moved up the hill and made camp for the final stages of our ice-train tests, practising towing the whole setup. It was only when we started the first pull of the complete ice-train that I realised how slow the trip was going to be; we'd be travelling at a speed that would frustrate even James May. As I write, we are currently two days into the fuel-drop trip and have covered 57 kilometres. But there's big stuff ahead, and I doubt I'll get much chance to be lazy during the next few months...