In 1898 De Dion-Bouton already build semi trailer busses, but the concept of the fifth wheel was only standarised and widely used after the 2nd world war. The closer you sit near the truck, the more uncomfortable, because of the direct connection to the truck chassis. (The where extensively used around the DAF factory in Holland for transporting their workers, and they where not very popular)
Circa 1930 the call for larger busses and the tax-law's that where on the weight of the tractor where a starting point for ever bigger busses based on it. In the 1920-1930 era there where many companies that build combination car's and truck's to convert between passengers and cargo. Besides taxes, it is a logical development to use semi-trailers. A truck can usually pull twice what it can carry. The truck needs more service and is the more likely component to break down. One spare truck can replace the truck part of many busses.
In building semi-trailer busses Kässbohrer of Ulm was the leading company. At the model change of 1937, Opel tractors where also used for semi-trailer busses. Leipzig and Dresden used them, Replacement of the heavy Berlin doubledeckers was attempted after the war. The roof lay-out of the Dessauer Mercedes bus is very revealing of the construction of all.
The pioneer situation seems to be Leipzig community transport. Speed of the combination is limited to 45 km/h.
Leizig Doubledecker trailerinfo:
Coachbuilder | Fahrzeugbau Schumann, Werdau |
Seats | 18 (belowdeck) + 28 (upperdeck) |
Stand places | 54 |
Standing height | 1.82 1.86 lower floor, 1.72 upper floor |
Lenght | 13 800 (with tractor) |
Width | 2 500 mm |
Height | 3930 mm (total) |
Own weight | 6 160 kg |
Total weight | 11 960 kg |
The trailer information is reportetly the 1939 version. Trailers ares seen with and without the "radverkleiding", the wheelcover. Compare the post war pictures. In day to day maintainance the probably where trouble.
A big Mercedes Benz tractor pulls a giant semitrailer bus revealing the roof layout. A side not often seen. This layout with a part roof opening with a sliding motion to the rear is seen on many period busses.
The lettering says Dessauer Strassenbahn. (Cable car company of Dessau)