Road train
From Wikipedia, the free encyclopedia
- This article is about road trains that carry freight. For trackless trains that carry passengers, see Trackless train.
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A road train is a trucking concept used in remote areas of Australia, United States, and Western Canada to move bulky loads efficiently.
A road train consists of a relatively conventional prime mover, but instead of pulling a single full trailer or a single semi-trailer the road train pulls more than one of them, typically two on busier roads but often more in outback areas of larger states like Western Australia, Queensland and the Northern Territory providing massive carrying capacity. The semi-trailers are connected with dollys and the full trailers are connected with drawbars.
Road trains are unwieldy, and pulling and maneuvering them safely is only possible because of the lack of traffic on Australia's Outback roads, and the terrain's flatness. The multiple trailers are detached and connected individually to multiple trucks when the road train gets close to populated areas.
Road trains are used for transporting all manner of materials, with livestock transport the most common. The cost-effective transport they have made possible has played a significant part in the economic development of these remote areas.
Overtaking a road train can be quite difficult (and on Australia's many dirt roads often impossible). Patience, assistance from the driver, and large amounts of clear road are required. Many road train drivers assist by blinking their right-hand turn indicators a couple of times to indicate that the road ahead is clear.
When the Road Train trailers are empty it is common practice to stack the trailers. At various points along the Highways special loading ramps are provided for stacking and unstacking the trailers. This is commonly referred to as "dog-up" or "dogging-up". In the more remote or less travelled areas the loading ramps are often just dirt or gravel pushed up to form a ramp. Quite often diff locks are required when dogging-up because of wheel slip on the loose surfaces. Also on major routes it is common place to see single trailers left on the side of the road to be hitched back up on the return trip or "back load".
In the United States, trucks on public roads are limited to three trailers (in some states only two), and the term "road train" is not commonly used. Triples are used for long-distance less-than-truckload freight hauling (in which case the trailers are shorter than a typical single-unit trailer), or resource (such as ore or aggregate) hauling in the interior west. Triples are typically marked with "LONG LOAD" banners both front and rear.
In the far north of Canada, road trains are used to transport materials on winter roads.
[edit] World's longest road trains
In 1999 the town of Merredin, Western Australia made it into the Guinness Book of Records, when Marleys Transport made a successful attempt on the record for the world's longest road train. The record was created when 45 trailers, driven by Greg Marley, weighing 603 metric tons and measuring 610 metres were pulled by a Kenworth truck for 8 km.
In 2003, the record was surpassed near Mungindi, New South Wales, by a road train consisting of 87 trailers and a single prime mover (measuring 1235 metres in length).
The next record was 1,442 metres, set by a driver in Kalgoorlie, Western Australia in a Kenworth owned by Doug Gould.
In 2006, a truck with 104 semi-trailers (at a length of 1,474.3 metres) claimed a new record at Clifton, Queensland.
[edit] Trailer arrangements
[edit] A-train
An A-train is a semi-trailer attached to an A-dolly. The A-dolly is connected to the tractor, truck or another trailer in front of it with a single draw-bar, thus giving it two articulation points and little roll stiffness.
[edit] B-train
A B-train is a semi-trailer attached to a fifth-wheel mounted on the rear of another semi-trailer.
[edit] C-train
A C-train is a semi-trailer attached to a fifth-wheel on a C-dolly. The C-dolly is connected to the tractor or another trailer in front of it with two draw-bars, thus eliminating the drawbar connection as an articulation point. One of the axles on a C-dolly is self-steerable to prevent tire scrubbing.
[edit] Also
Two or more full trailers attached to a truck and to each other by means of drawbars. One axle on each trailer is self-steerable.
[edit] See also
- Air brake (road vehicle)
- Brake
- Jackknifing
- Semi-trailer truck; this article covers large trucks such as road trains and articulated lorries
- Transport
