How 'Self-Driving' Trucks Connected the Australian Outback

Decades before autonomous vehicles, an ingenious engineering trick changed life in Australia’s arid, remote interior.

A trackless "road train" drives through the Australian outback.
Posnov / Getty

The trucks that roam the highways of the Australian outback are a lot bigger than the average 18-wheeler. Instead of towing one container, these road trains, as Australians refer to them, pull at least three self-tracking semitrailers behind them, which follow each other like train carriages. The trailers are packed with heavy goods—cattle, gas, coal, cars—and sent roaring through the continent’s interior to deliver supplies to coastal cities.

Fully loaded, road trains weigh up to 120 tons, and materialize on the shimmering horizon of outback roads as great mechanical beasts. As they pass at 70 miles per hour, you can feel the air velocity generated by the machine trying to suck you under the rig.

Road trains are as much a part of the outback as red dirt or Akubra hats, signifiers of a rugged, Mad Max mythology that has come to define Australia’s interior in the global imagination. But there was a time when these same road trains were expected to transform the outback from what one Australian historian has called “a passionate and prolific Earth never yet tamed” into a settled, flourishing region.

In a way, the road train was the self-driving car of its day, a cutting-edge technology of machine-guided transport that transformed life in the outback. But as a new generation of autonomous trucks now looms just on the horizon, the outback is poised yet again to be at the forefront of transportation.

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In the 1930s, the problem of providing outback communities with supplies occupied the minds of the Australian and British governments. While the cities and towns of the south were connected with train lines, the communities of the northern and central parts of the continent remained separated by great expanses of arid country. For decades, camels and cameleers imported from Afghanistan and Pakistan had serviced the few pioneering men and women who took a gamble farming or prospecting at distant outposts. But survival was tenuous, and in times of drought or famine, families had to walk off their properties or perish.

One solution—developed by a team of engineers in Britain—was to build a truck that behaved like a train, by attaching linked trailers to the back of a large vehicle. Although a simple idea, pulling this off required great mechanical ingenuity. Whereas train carriages were held in place by metal tracks, the truck’s trailers had to be able to follow one another around corners without any external guidance.

The technological breakthrough was to make the trailers self-tracking, a feat achieved by joining the front and rear axles of each trailer with a metal rod, so that when the wheels of the front axle turned in one direction, the rear axle pivoted in the opposite direction. Although somewhat counterintuitive, this mechanism allowed the wheels at the back of the trailer to delay their response to the movement at the front of the trailer, and pivot in exactly the same position on the road as the anterior wheels. This meant that any number of trailers could follow each other around bends without dragging or cutting corners, as if held in place by invisible tracks.

On its maiden Australian journey in 1934, the road train’s self-tracking trailers proved capable of navigating the 1,100 miles of red, rock-strewn flatlands and salt plains between Adelaide and Alice Springs. The morning the vehicle arrived in Alice Springs, the whole town turned out to greet it. Many were excited at the prospect of a stable supply chain. Others were wary of the British-made machine. A reporter for the Adelaide Advertiser wrote, “The Afghans and Aborigines, although interested in the big unit, viewed it with mixed feelings. One old Afghan said, ‘My people pioneered the transport in the outback, but the motor car has now come, and now they can run a train without building a line.’”

Indeed, for most cameleers, this imported machine signified the end of their time in Australia. They released their camels into the wild, and returned back from where they came. For many indigenous people, who had been living in the surrounding deserts for millennia, the road train was yet another foreign incursion into traditional homelands.

For the next decade, that one road train serviced remote outback communities, bringing supplies at regular intervals, while forging new tracks over sand dunes, alluvial flats, and stony plains. During the wet season, dry riverbeds would flood, and the driver would have to dismantle the truck, drive the lead vehicle across raging currents, and then tow the trailers over.

During World War II, these rugged tracks through dunes and riverbeds were transformed into great arterial highways by the Australian and U.S. militaries. Then, in 1946, the original road train—having driven more than 1 million miles—was decommissioned, its sluggish grunt not suited to the new asphalt roads.

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In the years after the war, several outback entrepreneurs—who remembered how the old British road train worked—purchased trucks and trailers off the U.S. military, and started rigging up their own self-tracking systems. With the benefit of the newly laid roads, these private operators could cart hefty cargo—like cattle and oil—to the big cities down south. Australia’s vast middle, which had for so long felt as far away from the cities as the open ocean, was connected to population centers along the coast. Just as the first road train had displaced the cameleers, these new long haulers put drovers—who had been moving cattle overland on horseback for the past century—out of work. Many had no choice but to sell their horses, forget the bush, and try to find factory jobs in the growing cities.

The road trains on outback highways today are, in many ways, the same as those that were carting supplies in the middle of last century. The men and women who drive these machines have come to occupy a similar place in the Australian imagination as the cameleers and drovers who came before them. They are the frontier dwellers, responsible for moving things through the barren places to populated centers. I once heard a road-train driver refer to himself as a “rubber-tire drover.”

But this charming comparison unwittingly portends what the future might hold for outback truck drivers. The Western Australian government recently announced that it will be testing an autonomous-driving technique called platooning on outback highways in the near future. Platooning technology is similar to the way self-tracking trailers work, in that it allows a chain of vehicles to automatically follow a single leading vehicle. But rather than relying on rods and axles to keep it in place, the platoon is connected via Wi-Fi, radar, GPS, and software. The capacity to share data directly from truck to truck means that the computer-controlled vehicles can move in tandem with uncanny accuracy, as if connected by an invisible chain.

Platooning technology still requires a human driver in the truck, but this may not be the case for long. There are already trucks in the Pilbara mines in the northwest of Australia that can haul iron ore without drivers, monitored by operators 750 miles south in Perth. As with the road trains of last century, the self-driving trucks of the coming decade will make Australia feel smaller and more connected—though this, too, will come with a cost. In the not-so-distant future, the people who move things around the continent will likely sit at a desk in front of a computer in a city, tracking the autonomous machines from a distance. When this day comes, truck drivers, like the cameleers and drivers before them, will have to bid farewell to their beasts and the outback track.