New Delhi: Road train as the word suggests is the train like long freight moving vehicle attached with a truck. This concept of trucking is used in core areas of Argentina, Australia, Mexico, the United States, and Canada for moving freight easily. In Australia it is known as Roadtrain but in the US it is commonly known as triples, turnpike doubles, and Rocky Mountain doubles for these long combination vehicles (LCV's). A road train generally consists of a tractor unit which instead of pulling one trailer it pulls two or more of them. So, a truck becomes a roadtrain when more than one trailer is attached to it. There are some specific trailer arrangements for road train according to the number of trailers they pull. Major arrangements are as follows: 1) B double or B Train: A B-double has a prime mover towing a specialized lead trailer that has a fifth-wheel mounted on the rear towing another semi-trailer. Its size must be maximum of 26 meters. 2) B Triple: It is quite same as B double but it has an additional lead trailer behind the prime mover. It runs by operator on strict permit on particular routes. B triple has maximum 33.5 meters of permit able size. 3) AB Triple: AB triple consists of a prime mover, a semi-trailer and a converter dolly. 53.5 meters maximum permissible size for AB Triple and other following arrangements. 4) BAB Quad: BAB Quad includes two B double units linked with a converter dolly. 5) C Train: It 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 drawbars. One of the axles on a C-dolly is self-steerable to prevent tire scrubbing. 6) Dog Trailer: Also known as Pup trailer, dog-trailer is any trailer that is hooked to a converter dolly, with a single A-frame drawbar that fits into the Ringfeder or pintle hook on the rear of the trailer in front, giving the whole unit three to five articulation points and very little roll stiffness.Watch more interesting pics of Road Train:
