B-Train

... B-Train (as related to the road transport or trucking industry) consists of two trailers linked together by a fifth wheel, and are up to 26 m (85 ft) long. The fifth wheel coupling is located at the rear of the lead, or first, trailer and is mounted on a "tail" section commonly located immediately above the lead trailer axles. In North America this area of the lead trailer is often referred to as the "bridge". The twin-trailer assembly is hooked up to a tractor unit via the tractor unit's fifth wheel in the customary manner. The main advantage of the B-Train configuration is its inherent stability when compared to most other twin trailer combinations and it is this feature above all else that has ensured its continued development and global acceptance. Although known as a B-Train in many countries, this particular twin trailer combination is also known by the term Interlink in Southern Africa and as a B-Double in Australia. [B-Train. Wikipedia]