At various stages in Army life, officers are given theoretical tests to stop them from falling asleep. They normally involve rescuing villages from volcanoes or moving tanks up the Amazon using canoes. It is the nature of said Army life that occasionally the theory becomes reality.

How do you move a 200-tonne hydroelectric turbine to a remote corner of Afghanistan? You can't fly it - there is no airstrip. There is a road, of sorts, but only in places and it is probably mined. Oh, and we have trucks, but they were made for the M1. They get testy in the sand.

This was the problem facing 16 Air Assault Brigade in Helmand this summer. As commanding officer of 13 Air Assault Support Regiment, I own the trucks that move water, food, fuel and ammunition around Helmand and I have the pleasure of commanding the indomitable men and women who drive them. In this case, I also owned the problem of the turbine.

The operation, codenamed Eagle's Summit, had been the subject of planning among the coalition for months. The US Agency for International Development has invested a lot of cash in this as part of a huge international effort to deliver electricity and water for the Afghans in Helmand.

The first problem was the road. It ran right alongside the green zone, the home to most of Helmand's population but also of those Taleban still up for a fight. The Pathfinders, 16 Brigade's elite reconnaissance troops, gave us a break when they discovered what looked like an alternative route through the desert, away from the Taleban. In classic military fashion, 500 pages of plans went into the bin, whiteboards were cleaned and we started anew.

Our bit was simple. Get the turbine on to big trucks and sneak it through the desert before the Taleban work out what's going on.

Soldiers of 3 Para would secure the hardest stretch of the road, the final five miles through the Taleban-held town of Kajaki. I just had to get to them. At the same time soldiers of 2 Para would make it look like we were going through the green zone, to fool the Taleban. We assembled a force of around 400 soldiers for the job. The Pathfinders went ahead to talk to the villagers and “feel” for the enemy. The Queen's Royal Lancers went next in their Viking armoured vehicles and they physically sat on the dangerous bits of the route, watching for signs that the enemy might try to ambush us or lay mines in our path.

Next went the engineer group with searchers who could find and then destroy enemy mines and Royal Engineers who repaired the desert track so it could take the turbine trucks. In some cases they literally built the road from scratch. At the back came the turbine, in the logistic group, carried on more than 40 transporters that creaked and groaned as their heavy loads shifted precariously over every small lump and bump, blowing hydraulic lines and tyres every few miles.

Early signs were not good. Within one mile of leaving tarmac roads we broke our first trailer and found our first mine. This very much set the tone. The second day we made only nine miles; breakdowns, wadis (dry riverbeds) and the occasional cheery rocket from nearby villages slowed us to a crawl. The following day the pace increased a little and we reached the Ghorak Pass, a beautiful if desolate spot that we had been concerned would make an ideal ambush site. It is one of those quirks of military life that all scenery is subjected to the “ambush suitability test” before its loveliness can be appreciated. As we travelled, large loudspeakers on our trucks proclaimed to some startled villagers (who admitted we were the strangest and most interesting thing they had ever seen) that we were bringing power to Southern Afghanistan. They were thrilled by the idea of getting some electricity.

Our creeping two-mile-an-hour pace continued to the edge of Kajaki and on the nod from 3 Para, who had done a superb job of securing the town, we then made what I - forever the optimist - hoped would be a dash up the last five miles. It took us eight hours in darkness. One young driver was injured as he repaired his battered vehicle and its suspension collapsed, trapping him under 65 tonnes of trailer and load. He is now in the care of Selly Oak Hospital, Birmingham, and thankfully on the path to full recovery.

By the time we reached the dam we have travelled for five days; for two nights there had been no sleep and for the rest, three hours at best. We were a little shabby. In a surreal moment we took the opportunity for a dip in the lake at the dam, again a spot of outstanding beauty. At this stage there was no time for celebration or reflection; we had to get back down the same route and this time the Taleban knew we were coming.

We were a little faster going back but not much. That slowed when the Taleban finally woke up to us and we were caught in a very clever ambush near a small village called Moshak. A mine stopped our front vehicle and shortly after another caught us at the rear, injuring three soldiers who were blown clear of their Land Rover. Then the rocket-propelled grenades came in, with a distinctive whoosh. An American vehicle coming to assist took a direct hit, killing one of its crew and turning it into an orange fireball. At that point all hell broke loose as we were fired upon from at least four different places. For all of us the reaction was instinctive. We quickly returned fire, the convoy's force protection troops in Land Rovers darting forward to pin the enemy down.

Identifying a nearby scrubby wood as the main problem, we called in close air support. The three wounded soldiers were all lucky: a few holes to be patched and some very stiff necks, not least for young Private Phillip Jenks, who had been blown up for the third time.

The final stretch dragged impossibly. The theory test returned. If it could go wrong, it did, in lots of little ways. Trucks broke, tracks weren't suitable, radio antennas snapped. There were even a few final rockets of farewell from the Taleban. We returned nonetheless, pulling into Camp Bastion more bearded, slightly thinner but now very definitely able to relax, laugh and be far too pleased with ourselves.

We are under no illusions that a lot more work will be required to get the dam to the point where it can provide electricity for millions of people and irrigate miles of arable land. But we are glad to have played a small part in this huge project. The front-page news we had become was a bit of a surprise.

In characteristic fashion Lance Corporal Danielle Hanwell, a radio operator, said quickly: “Sir, if you speak to the press, tell them not to forget it was the 'loggies that got it there. Unsung heroes we are.”

Job done, Danielle.

Lieutenant-Col Rufus McNeil, Commanding Officer of 13 Air Assault Support Regiment, was responsible for Operation Eagle's Summit. He is still serving in Helmand province

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