I don't. As far as I know the N&W Class J is perfection itself. :)
I remember looking at this in the Complete Collection - I'll look a bit later and see if I can find it again.
If there is reduced or zero overbalance, something has to counteract the nosing tendency caused both by piston thrust and inertial load. In the article in question, it was noted that stiff lateral compliance was provided for both the leading and trailing truck, resisting (with the longest possible moment arm) the tendency for the chassis to yaw about the axis of the main driver.
Naturally this force is applied at the pivot pin of the lead truck, and at the rear of the two-axle trailer, giving a longer effective 'wheelbase' and, more directly, greater resistance in curves or lateral track displacements. Ideally the drive would be separated from the guiding, with the drivers given a bit more flange clearance and the steering being done mainly with the leading and trailing trucks (and the lead driver axle given a bit of controlled lateral motion to absorb shock of any insufficiently-spiraled curve or turnout, but probably not as much as on a more 'conventional' locomotive.
The drawback to this approach is that the effective wheelbase being longer, the locomotive is also stiffer and more prone to derail -- including if it encounters any small lateral displacement in the track which a diesel would easily and quietly accommodate. If I remember correctly 611 was notorious for finding these and 'announcing their presence'.
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