Richard, I'm sure your comment regarding the support jacks is quite correct and that one usually associates these jacks being fitted to wireless/radar vans etc. However, one does not normally think of van trailers of this type being so heavy that they needed eight, or even sixteen, wheels.
So far, the comments on this thread seem to me to be suggesting that we think this trailer was designed to carry quite a heavy payload, hence the large number of wheels to distribute the weight. If this was the case, why would one fit support jacks to a trailer intended to convey heavy loads ? Is that usual practise ?
Talking of unusual arrangements, has anyone on here ever before seen an arrangement where the axle rides on top of the leaf spring and not, in the conventional manner, under the spring ?
My current theory is that this trailer was built using the bed of a cut down van type trailer and that the very interesting undercarriage may also have been workshop built, by reducing standard track army surplus trailer axles, and that these axles were fitted above the leaf spring to lower the bed so that plant could be more easily driven up ramps onto it.
It looks to me as though the farmer engineer who may have built this marvelous trailer may have used gas to cut away a section of chassis to accommodate the axle being fitted above the springs and to get a spanner on those nuts. I don't think Dyson would have done it quite like this.
Does this look "right" to you ?
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Antony mentions another similar trailer on a farm near him. I'd be very interested to see 'photos of that one and also to hear what evidence there is that this trailer was ever fitted with a braking system. I can see brake drums but, not from the 'photos, any sign of a braking system. Without brakes, out on the road, in the wet, this trailer would soon be round giving the radiator of the towing vehicle a french kiss.