A 1:53 scale model of a road train - The history

   
    I am an enthusiast of models of railroads, and of industrial vehicules, too. Particularly of great trucks. Browsing the Internet with a search engine, I found the Tonkin Replicas and the Hank's Web Site. Hank has a page wich tells where to buy Tonkin Replicas.
    So I started to purchase some Precision Series 1:53 scale replicas. See "My model trucks".
    One of my last purchases was a “TONKIN REPLICAS MANAC 48' TRAILER 1/53RD (O SCALE) (PRECISION SERIES)” (image from Whitebear Studios LLC ). At first I devised to carry out a wooden load for the trailer; but soon I realized that a trailer alone was not complete. It required a tractor!
    Because in my collection I did not have a Peterbilt, I decided to purchase a “TONKIN REPLICAS PETERBILT 379X CAB (YELLOW) PRECISION SERIES 1/53 (O SCALE)” (image from Whitebear Studios LLC ).
    But still I was not satisfied. Browsing the pages of Hank, I found the pictures of Richard Mohr Truck Collection, and I was struck by the long, awesome australian road trains. Having seen the availability of Tonkin spare parts, like “1/53RD (O SCALE) DUAL TRAILER W/AXLES AND SUSPENSION” and “AIR HOSE SET 1/53RD (O SCALE)” (images from Whitebear Studios LLC ), I established to build a road train similar to the australian ones, using the Peterbilt tractor and the Manac trailer.
    The view of such road trains is very spectacular, particularly for italian (and european) people, because local regulations do not allow more than one trailer for every truck. So I will shortly explain the main combinations.
    Generally, the australian road trains are made of a tractor (obviously) and from 2 to 5 trailers. The more frequent combination is made of 4 trailers. Some examples follow; all the photographs are drawn from Hank's web site. As required by Richard Mohr and Martin Phippard (hosted by Hank), you may download any image for personal or non-commercial use only.
    The first possibility for connecting 4 trailers is to set up a B-Train (B-Double in Australia) configuration with 2 trailers more behind that, like this .
    What does “B-Double” mean? Martin Phippard, within Hank's web site, says: “a B-Train consists of two trailers linked together by a fifth wheel. This is located at the rear of the first, or lead trailer, and is usually mounted on a ‘tail’ section commonly located immediately above the lead trailer axles. When linked together to form a twin-trailer combination or B-Train set, this may be coupled to a tractor unit via the tractor’s fifth wheel in the customary manner”.
    The B-Train can be seen as an evolution of the A-Train combination. Martin Phippard explains that “an A-Train is similar to a regular tractor/semi-trailer combination with a following full trailer. The ‘full’ trailer is usually composed of a single or double-axle dolly converter  (‘A’ dolly) that has a drawbar that connects to the rear of the first semi-trailer and has a fifth wheel mount for the second semi-trailer. The drawbar of the dolly is usually fitted with a pintle ‘eye’ that connects to the pintle ‘hook’ which is mounted at the rear of the first semi-trailer. A second semi-trailer is hitched to the dolly-mounted fifth wheelIn other words, the dolly converts a semi-trailer to a full trailer.
    The second possibility is the “Double B-Double”: a four-trailer combination which, as its name suggests, is made up of two B-Trains (or B-Doubles) hooked together by a dolly converter. The particular combination of the picture is slightly different from this scheme, because the first semi-trailer is not hitched to a tractor, but to a dolly, which in turn is hooked to a straight truck, equipped with a loading device of the same type of the trailers.
    Finally, a “2AB” combination can be set; it can be seen as a double B-Double, were one of the two B-Trains is replaced by an A-Train.
    In the past, up to 6 trailers were connected. In Australia in the 1990s a six-trailer combination configured as a "3B" (that is, made up of three short B-Doubles) was afterwards abandoned, because of stability problems, in favour of a B-Triple coupled to a B-Double.
    Designing my model, I limited myself to a 3 trailers using the “B-Triple”; as Martin Phippard says, “this is a three-trailer combination hooked together in the same way as a B-Double, but incorporating two trailer-mounted fifth wheels rather than one”.
    I made a summarizing table with all the combinations that I explained. Obviously the real shapes and dimensions can vary a lot; moreover tractors and trailers can be not only of tandem-axle type, but tri-axle, too. Lastly, trailers (and tractors) can have intermediate self steering push-axles. 

     
(The pictures of the model)
(The construction of the model)