Road Trains, Max Loads and other such semi nonsense

[Spencer]

I've recently reconnected to Car Wars, which I played in the 80s when I was a youngster. Discussions with an old friend prompted this thread.

In Australia, the truckers use a rig setup called a Road Train. simply put, this is 2 or 3 full-sized semi trailers hooked to a single heavy hauler tractor. This prompted some discussion on what kind of rules would apply to a Road Train, or for that matter how to build a heavy hauler. I've has some thoughts:

1. Max Load still applies insofar as to calculate top speed.
2. A heavy hauler can use a specific type of huge engine, just like they do IRL. This would have to be custom designed. The advantage would be that the tractor would have plenty of max weight for pulling; the disadvantage would be that such engines would require practically all the spaces available in the tractor. These engines would also be expensive.
3. The first trailer would have to have a hauling dolly and hitch, which would be heavy and be a potential weak point in the system (broken dolly=everything behind it comes uncoupled and crashes). The hitch system would be based on the drawbar and need a heavier load limit; it would also have to have several tires to allow it to function properly.
4. Fuel/PP usage would be a massive limiter. Road Trains would use PP/fuel at (total vehicle weight/total max load) times the rate, rounding up to the nearest PP/gallon.
5. Heavy Haulers could also be used for oversized loads on flatbed trailers.
Thoughts?