Road Trains Roam The Backroads Of Australia | Hackaday

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Trains and the railways they run on are a great way to move lots of stuff, or lots of people, a long way. Steel wheels on steel rail can shift great loads at good speeds and railways remain a backbone of logistics for this very reason. The only problem is that they require a great deal of initial investment to build and plenty of maintenance to keep them functional over time.

These concerns can make a railway a difficult proposition when it comes to getting large amounts of goods in and out of remote areas. It’s a problem that Australia faces, with settlements far off the beaten track that are nevertheless in need of high-throughput freight connections. And if you can’t go rail, you go road… in a big way.

Heavy Haulers

The simple fact of Australia’s geography is that there are towns and cities separated from each other by thousands upon thousands of kilometers. It’s often desirable to move goods to and from these places, along with remote mines and farms buried in the country’s vast, dry interior. However, it has never been practical to link all these disparate locales by permanent railways. The distances have always been too vast, and the freight volumes not quite high enough to justify the expense. At the same time, relying on trucks alone was seldom economically convenient.

An MGM Kenworth C509 pulling a 60-meter A-quad configuration in Western Australia. Credit: CC BY 4.0<br>" data-large-file="https://hackaday.com/wp-content/uploads/2026/07/MGM_C509_Quad_Road_Train.jpg?w=800" class="wp-image-1131425 size-medium" src="https://hackaday.com/wp-content/uploads/2026/07/MGM_C509_Quad_Road_Train.jpg?w=400" alt="" width="400" height="200" srcset="https://hackaday.com/wp-content/uploads/2026/07/MGM_C509_Quad_Road_Train.jpg 960w, https://hackaday.com/wp-content/uploads/2026/07/MGM_C509_Quad_Road_Train.jpg?resize=250,125 250w, https://hackaday.com/wp-content/uploads/2026/07/MGM_C509_Quad_Road_Train.jpg?resize=400,200 400w, https://hackaday.com/wp-content/uploads/2026/07/MGM_C509_Quad_Road_Train.jpg?resize=800,400 800w" sizes="(max-width: 400px) 100vw, 400px" />An MGM Kenworth C509 pulling a 60-meter A-quad configuration in Western Australia. Credit: SquiddyFish, CC BY 4.0<br>The solution was straightforward, and surprisingly simple—bigger trucks hauling more trailers. In the local parlance, a road train consists of a prime mover (or tractor) that hauls two or more trailers.

The official definition from the Heavy Vehicle National Law excludes the standard B-Double configuration that is regularly seen across the country. Instead, a road train could be a longer A-Double configuration, or even one of a variety of combinations involving three or four trailers being hauled by a single prime mover, like a B-Triple or a BAB Quad. The A and B designations refer to the type of coupling used. A-type refers to drawbar-based couplings, while B-types are fifth-wheel or turntable-type couplings. A truck or road train setup is thus referred to by the couplings that make up the consist.

A four-trailer BAB-Quad road train in Marla, South Australia. Credit: Caroline Jones, CC0<br>" data-large-file="https://hackaday.com/wp-content/uploads/2026/07/Road_train_in_Marla_South_Australia.jpg?w=800" class="wp-image-1131426 size-medium" src="https://hackaday.com/wp-content/uploads/2026/07/Road_train_in_Marla_South_Australia.jpg?w=400" alt="" width="400" height="245" srcset="https://hackaday.com/wp-content/uploads/2026/07/Road_train_in_Marla_South_Australia.jpg 4031w, https://hackaday.com/wp-content/uploads/2026/07/Road_train_in_Marla_South_Australia.jpg?resize=250,153 250w, https://hackaday.com/wp-content/uploads/2026/07/Road_train_in_Marla_South_Australia.jpg?resize=400,245 400w, https://hackaday.com/wp-content/uploads/2026/07/Road_train_in_Marla_South_Australia.jpg?resize=800,489 800w, https://hackaday.com/wp-content/uploads/2026/07/Road_train_in_Marla_South_Australia.jpg?resize=1536,940 1536w, https://hackaday.com/wp-content/uploads/2026/07/Road_train_in_Marla_South_Australia.jpg?resize=2048,1253 2048w" sizes="(max-width: 400px) 100vw, 400px" />A four-trailer BAB-Quad road train in Marla, South Australia. Credit: Caroline Jones, CC0 We count 12 shipping containers.<br>The longest road train configurations of three or four trailers typically range up to 53.5 meters in length and over 135 tons in weight, per the rules laid down by the National Heavy Vehicle Regulator, though even longer configurations are used in some specially-permitted or off-highway roles in mining or agricultural industries.

These long consists are typically pulled by large prime movers with anywhere from 500 to 700 horsepower and 1500 to 2000 pound-feet of torque. Ultimately, it doesn’t actually take a grand amount of power to get even a very heavy load moving; it’s the torque that helps the most, anyway. The bigger challenge is actually stopping, and that takes great care and makes road trains...