Dolly (trailer)
A dolly is an unpowered vehicle designed for connection to a tractor unit, truck or prime mover vehicle with strong traction power. United States. Classification by axle configuration. There are several types of dolly bogie: Classification by coupling configuration. There are two basic types: Australia. Converter dollies are used in road trains in Australia, most commonly with two or three axles and a hinged drawbar. They are also frequently referred to as "road train dollies". The C-dolly design is not allowed in Australia, as it prevents articulation between the dolly wheels and the axles of the truck  or trailer in front of the dolly. Australian rules require articulation between axle groups. Low-loader dollies- which present a kingpin rather than a drawbar coupling- are used with many low loaders to allow heavy cargo to be carried without overloading the wheels of the prime mover or the low loader.