[excuse-me]

For the requirements - a heavy but symmetric load over narrow roads - it's a pretty good solution. At least until you have to stop!

Interestingly, trading inherent stability and rigidity for more control effort to give you a lighter more manouverable design is something we have only just "reinvented" with some fighter aircraft (and the Segway ;-)

In spite of having active/computer control systems fro 30years we still do seem to stick to the 19C railway engineering mentality of - build it big/strong/stable/rigid/heavy