Austro-Daimler » B-Zug
When Skoda started working on their new generation of super-heavy guns, the 24cm M.16, the 38cm M.16 and the 42cm M.16, it was soon obvious that these new artillery pieces needed a new type of transportation, if they ever would be as mobile as their famous predecessor, the 30.5cm M.11. The man that was given the opportunity to design such a transport, was none other than Dr Ferdinand Porsche, who at this time worked for Österreicher Daimler in Wiener Neudtadt. And his solution was to update the design of A-Zug. He decide to use a so called gasoline-electric engine. A 6-cylinder 20.32 liter gasoline engine drove a generator, and the generator in it's turn drove two electrical engines, one for each back axle. Note that the generator car did not pull the trailer, as much as gave it power: the same generator also fed eight electrical motors on a four axle trailer - which contained one of the disassembled parts of the gun.
The whole design was quite complex, perhaps overly so in modern eyes. But it worked. On good road with gentle gradients, one of these B-Zug tractors could pull two trailers, to a maximum speed of 12 km/h. This could be increased to 14 km/h if the number of trailers were reduced to only one. With one trailer, a gradient of 26º could be negotiated, with two trailers a gradient of only 20º. All in all it was quite a handsome movement capacity, at least compared to all contemporary designs. And it was very reliable, as many systems had back-ups, and as the design was very robust. But all this came to a price. As mentioned above, the B-Zug was also a very complex design. Maintainance and even starting was difficult. The fuel filter had to be changed empitied every 2-3 hours, and every 10 km the valve gear had to be lubricated, etc. Still, it was seen as the perhaps most modern tractor of it's day, and they were admired whenever they appeared.