Hi Andy, like the pictures...
BTW here is one prototypical mass (whole industry?) application of using equalization and not using horn blocks.
And its proto-scale, RTR, manufactured and inexpensive model equivalent.
..but I'm beginning to wonder if some of the differences being aired here aren't as much "cultural" as anything else. When you think of a 4 wheel truck the images that come to your mind are as above. When I think 4 wheel truck I get something more like
(My apologies to Gareth Thomas for having pirated this picture off his Not so Edwardian wagons
If I wanted a wagon with bogies like yours I would fit them like a shot, however appropriate wagons in 1930's eastern England were thin on the ground, as a solution to the traditional UK 4 wheel wagon I'm not clear they have much to say. I will steer clear of coach bogies for now.
In terms of solutions to the UK 4 wheel wagon problem, this is something that the P4 community has had some practice at, given that orthodoxy suggests some form of suspension is de rigueur (but let us not have that discussion right now). The compensated method of choice (one fixed and one rocking axle) works well enough to have made P4 practical, but experience over time has shown its limitations. Having one pivot point in the centre at one end, particularly on cast white metal vans that have a high Centre of Gravity, has an unfortunate effect on their stability. Most particularly when being pushed. (More cultural differences, the buffering forces involved with UK pattern buffers again is not a normal part of the American railroad modelling experience and I'm not sure you have too many cast white metal van kits either). While it is just possible this incipient instability could lead to such a wagon toppling over on a track with a lot of cant, more commonly it is experienced by a wagon derailing while being pushed round a corner because it has lifted a wheel.
The development of spring systems which provide exactly the "spring at each corner" that has concerned you, has proved to be significant not only in terms of producing a wagon that rides better, but also because it doesn't suffer its compensated brethren's bad habits. Not to mention leaving the wagon nut free to complete the under frame detail uncomplicated by the presence of rocking W irons. Cue another picture pirated from Gareth.
So why don't such wagons full fill your table with springy legs prophecy?
Proto87Stores wrote:.. A similar vehicle chassis that is "merely" fully equalized will be as firm and stable as on absolutely flat track.
To visualize this better, consider the classic four legged table in the restaurant with the uneven floor. Instead of stabilizing it with a wedge or an equalized pair of legs, the waiter puts springs on all four legs. And then you order a brim full bowl of soup and a plate of peas . . . .
The simple answer is that their springs are sufficiently damped by the way the axle bearing carriers rub against the fixed W irons, and the net result is a significant improvement on compensation. I'm not saying that it isn't possible to design a sprung suspension that does full fill your worst fears, when I was playing with wagon springing some years ago I managed just that, but the now accepted design does not. The same "sufficiently damped" by fiction on the bearing blocks argument applies to CSB sprung locos too, which equally do not display any tenancy to isolate on their springs.
And yes I know Compensation and Equalisation are not the same thing. There are several Coach Bogie designs about in the UK with fixed axle bearings in sides that move relative to one another which will be much closer to your truck design. I think the jury is out on whether there are significantly better or worse or different from than the fully sprung variety, or if the orthodoxy really does apply a fully rigid bogie doesn't do just as well.