Road train
A road train, also known as a land train or long combination vehicle, is a semi-trailer truck used to move road freight more efficiently than single-trailer semi-trailers. It consists of two semi-trailers or more connected together with or without a prime mover. It typically has to be at least two trailers and one prime mover. Road trains are often used in areas where other forms of heavy transport are not feasible or practical.
History
Early road trains consisted of traction engines pulling multiple wagons. The first identified road trains operated into South Australia's Flinders Ranges from the Port Augusta area in the mid-19th century. They displaced bullock teams for the carriage of minerals to port and were, in turn, superseded by railways.During the Crimean War, a traction engine was used to pull multiple open trucks. By 1898 steam traction engine trains with up to four wagons were employed in military manoeuvres in England.
In 1900, John Fowler & Co. provided armoured road trains for use by the British Armed Forces in the Second Boer War. Lord Kitchener stated that he had around 45 steam road trains at his disposal.
A road train devised by Captain Charles Renard of the French Engineering Corps was displayed at the 1903 Paris Salon. After his death, Daimler, which had acquired the rights, attempted to market it in the United Kingdom. Four of these vehicles were successfully delivered to Queensland, Australia, before the company ceased production upon the start of World War I.
In the 1930s/40s, the government of Australia operated an AEC Roadtrain to transport freight and supplies into the Northern Territory, replacing the Afghan camel trains that had been trekking through the deserts since the late 19th century. This truck pulled two or three Dyson four-axle self-tracking trailers. At, the AEC was grossly underpowered by today's standards, and drivers and offsiders routinely froze in winter and sweltered in summer due to the truck's open cab design and the position of the engine radiator, with its cooling fan, behind the seats.
Australian Kurt Johannsen, a bush mechanic, is recognised as the inventor of the modern road train. After transporting stud bulls to an outback property, Johannsen was challenged to build a truck to carry 100 head of cattle instead of the original load of 20. Provided with financing of about 2000 pounds and inspired by the tracking abilities of the Government roadtrain, Johannsen began construction. Two years later his first road train was running.
Johannsen's first road train consisted of a United States Army World War II surplus Diamond-T tank carrier, nicknamed "Bertha", and two home-built self-tracking trailers. Both wheel sets on each trailer could steer, and therefore could negotiate the tight and narrow tracks and creek crossings that existed throughout Central Australia in the earlier part of the 20th century. Freighter Trailers in Australia viewed this improved invention and went on to build self-tracking trailers for Kurt and other customers, and went on to become innovators in transport machinery for Australia.
This first example of the modern road train, along with the AEC Government Roadtrain, forms part of the huge collection at the National Road Transport Hall of Fame in Alice Springs, Northern Territory.
In 2023, Janus launched the first battery electric triple road train with 620 kWh battery, also the world's heaviest street-legal BEV truck at 170 tonnes.
Usage
Australia
The term road train is used in Australia and typically means a prime mover hauling two or more trailers, other than a B-double. In contrast with a more common semi-trailer towing one trailer or semi-trailer, the diesel prime mover of a road train hauls two or more trailers or semi-trailers. Australia has the longest and heaviest road-legal road trains in the world, weighing up to.Double road train combinations are allowed on some roads in most states of Australia, including specified approaches to the ports and industrial areas of Adelaide, South Australia and Perth, Western Australia. An A-double road train should not be confused with a B-double, which is allowed access to most of the country and in all major cities.
In South Australia, B-triples up to and two-trailer road trains to are permitted on only a small number of approved routes in the north and west of the state, including access to Adelaide's north-western suburban industrial and export areas such as Port Adelaide, Gillman and Outer Harbour via Salisbury Highway, Port Wakefield Road and Augusta Highway before 2017. A project named Improving Road Transport for the Agriculture Industry added of key routes on which it is permitted to operate vehicles over in 2015–2018.
Triple road trains operate in western New South Wales, western Queensland, South Australia, Western Australia, and the Northern Territory, with the last three states also allowing AB-quads. Darwin is the only capital city in the world where triples and quads are allowed to within of the central business district. As of 2025, triple road trains are only allowed on a single highway in New South Wales, which is the Mitchell Highway between North Bourke and the Queensland border at Barringun, spanning a distance of approximately 130 km.
Strict regulations regarding licensing, registration, weights, and experience apply to all operators of road trains throughout Australia.
Road trains are used for transporting all manner of materials; common examples are livestock, fuel, mineral ores, and general freight. Their cost-effective transport has played a significant part in the economic development of remote areas; some communities are totally reliant on regular service.
When road trains get close to populated areas, the multiple [|dog-trailers] are unhooked, the dollies removed and then connected individually to multiple trucks at "assembly" yards.
When the flat-top trailers of a road train need to be transported empty, it is common practice to stack them. This is commonly referred to as "doubled-up" or "doubling-up". If many trailers must be moved at one time, they are sometimes triple-stacked, or "tripled-up".
Higher Mass Limits Schemes are now extant in all jurisdictions in Australia, allowing trucks to carry additional weight beyond general mass limits. Some roads in some states regularly allowing up to 4 trailers at long and. On private property such as mines, highway restrictions on trailer length, weight, and count may not apply. Some of the heaviest road trains carrying ore are multiple unit with a diesel engine in each trailer, controlled by the tractor.
Diesel sales in Australia are around 32 billion litres, of which some is used by road trains. In order to reduce emissions and running cost, trials are made with road trains powered by batteries.
United States
In most of the United States, trucks on public roads are limited to two trailers. Some states allow three trailers, although triples are usually restricted to less populous states such as Idaho, Oregon, and Montana, plus the Ohio Turnpike and the Indiana East–West Toll Road. Triples are used for long-distance less-than-truckload freight hauling or resource hauling in the interior west. Triples are sometimes marked with "LONG LOAD" banners both front and rear. "Turnpike doubles"—tractors towing two full-length trailers—are allowed on the New York Thruway and Massachusetts Turnpike, Florida's Turnpike, Kansas Turnpike as well as the Ohio and Indiana toll roads. Colorado allows what are known as "Rocky Mountain Doubles" which is one full length trailer and an additional trailer. The term "road train" is not commonly used in the United States; "turnpike train" has been used, generally in a pejorative sense.In the western United States LCVs are allowed on many Interstate highways. The only LCVs allowed nationwide are STAA doubles.
On private property such as farms, highway restrictions on trailer length and count do not apply. Bales of straw, for example, are sometimes moved using wagon trains of up to 20 trailers extending an eighth of a mile and carrying a total of 3,600 bales.
Europe
In Finland, Sweden, Germany, the Netherlands, Denmark, Belgium, and some roads in Norway, trucks with trailers are allowed to be long. In Finland, a length of has been allowed since January 2019. In Sweden, this length has been allowed on several major roads, including all of E4, since August 2023. 34.5 meters allows two 40 foot containers.Elsewhere in the European Union, the limit is . The trucks are of a cab-over-engine design, with a flat front and a high floor about above ground. Scandinavian countries are less densely populated than most of the rest of the EU, and travel distances there, especially in Finland and Sweden, are long. Until the late 1960s, vehicle length was unlimited, giving rise to long vehicles to cost effectively handle goods. As traffic increased, truck lengths became more of a concern and they were limited, albeit at a more generous level than in the rest of Europe.
In the United Kingdom in 2009, a two-year desk study of Longer Heavier Vehicles, including up to 11-axle, long, combinations, ruled out all road-train-type vehicles for the foreseeable future.
In 2010, Sweden performed tests on log-hauling trucks, weighing up to and measuring and haulers for two 40 ft containers, measuring in total. In 2015, a pilot began in Finland to test a 104-tonne timber lorry which was and had 13 axles. Testing of the special lorry was limited to a predefined route in northern Finland
Since 2015, Spain has permitted B-doubles with a length of up to and weighing up to 60 tonnes to travel on certain routes. In July 2024, after 5 years of testing, HCTs have been permitted on Spanish territory, with lengths of up to 32 meters and 70 gross tonnes.
Since 2016, Eoin Gavin Transport, Shannon and Dennison Trailers, Kildare have been trialling B-doubles on the Irish motorways. In Feb 2024, The Pallet Network announced four B-doubles to operate between Dublin, Cork and Galway.
In 2020, a small number of road trains were operating between Belgium and the Netherlands.