What is the difference between "A-Zug", "B-Zug" and "C-Zug"?

[a-h]

"A-Zug", "B-Zug" and "C-Zug" — this is a heavy car train of Ferdinand Porsche. What is the difference? Because the truck was for "B-Zug" and "C-Zug" the same — Artillerie-Generatorwagen M16.

http://www.landships.freeservers.com/mg ... review.htm

[Bernaschek]

I have found only those links immediately, showing the "C" train; dark memories of articles i read once don't tell me much but it's especially the carrying capacity.

http://www.hybrid-vehicle.org/hybrid-ve ... dwehr.html

http://press.porsche.com/archive/produc ... istory.pdf

the Porsche link interestingly doesn't mention the 1905 prototype of a 4X4 armoured car, that is said to have frightened the emperors horse and so was not further regarded
http://de.wikipedia.org/wiki/Radpanzer_(Österreich)

here they talk about the evolution of the concept, with the "C" train the last one

http://www.schule.de/bics/son/verkehr/p ... 002_67.htm