When Allenby advanced on Jerusalem his army was supported by over 230 Holt tractors some drawing land trains of tracked trailers. I know that a very large number of Holts was used by the British army in most if not all theatres but I've never seen any evidence of such trailers elsewhere. Was this a purely ME development?
I suspect you need to look for industrial and agricultural machinery sources for something like that. For example, a modelmaker who specialises in farming and industrial machiniery produces a kit of a Linn-Wheeler trailer, a tracked trailer (http://www.riograndemodels.com/Images/LargeHO/3078.jpg). It's not the same as yours, but it does seem to show the use of such things quite early on.
The trailers in question are a product of the Holt Manufacturing Company of the USA. Actually, Holt marketed 3 versions of trailers; this being the largest, and the type procured by Britain.
As a matter of trivial interest, the USA supplied a considerable number of Holt tractors to the Entente powers; both before, and after America's entry into the conflict. The following figures can be appreciated:
Britain: 1,362 Holt 75 , 243 Holt 120
France: 18 Holt 75 , 352 Holt 45
As further clarification, the Holt 45 was a fully tracked caterpillar of 45HP. The Holt 75 was fitted with the tricycle steering and of 75HP, while the Holt 120 was a lengthened version of the 75 with two extra engine cylinders and of 120HP.
I have photo evidence of their use in the 1916 US incursion into Mexico, but none of the Great War European theatre. That doesn't mean they weren't there; I simply have no evidence of their appearance there.
Incidently, the photos posted are all of the Holt 75 with the 4 cylinder engine.
You posed an interesting question the other day, on the Holt trailer wagons; I have just now had the time to respond, because unfortunately, I have been unable to find all of my information on these things. I do know this much: They were designed to provide a simplified and improved trailer wagon of large capacity in hauling very heavy loads under such conditions as are encountered in military operations. Excerpt from Patent N#130,635.
As Jack pointed out, there were 3 designs. The one you have posted is the large heavy duty version, I have attached a drawing from the above patent, which shows the large lighter duty trailer, also the first version had a single track. The second drawing set comes from the same patent, it show some more details of the chassis.
From my research all three versions of these wagons were shipped to Egypt. They were also slated to be used on the Western front, I have a Quarter Masters Log that states the following: On hand March 21, 1918 3 tracked trailers, to be used in tandem with the Holt Machines. This is from a English QM stationed in France.
Now I know that does not directly answer your question, but that’s the best I can do. I have never found any photos of them being used in France,(or any other theater, other than Egypt etc.,) I do no as Jack also pointed out they were used in Mexico by the American Army. These trailer were slightly different than there English counterparts.
I do have more photos of all three English types, as well as the earlier American types, if interested. It may take awhile to find them though.
Does anyone know of models of these tractors? Would be something for MGM to have them in their assortment. (in other words: come on Mario, start building!)