Thanks to all of you for the information and suggestions. I was mostly looking for justification for the big Crocodiles behind my LMS power. I'll probably commit to one of the wagons when budget allows.
I don't have a layout myself, yet. I mostly run on either our club's host's layout, or our club layout itself. We do have one tunnel, plus a couple of road overbridges. May end up being a display piece.
Would grouping-era exceptional loads ever be tendered across multiple lines? If so, which company would furnish the wagon - the origin railway or the delivering railway?
Worth considering on some of those gaps are the LB&SCR's traffic. They didn't handle all that much freight. So, a lot of the usual freight loco development didn't happen. I think there was a pretty sizeable gap between the K & their immediate predecessors.
I went with the IPA mentioned by @PenrithBeacon. Cleaned up well. I was even able to get the wheels out and back in with no issues.
Added oil, then checked directions. Accidentally oiled the hornblocks. How much of an issue will that be in the long run?
Odd thought I had, but would it be possible to stand-off the irons from the front of the bogie? Or, mount them in a slot with a link to the bogie? Might be a little fiddly or unreliable, but could be a good compromise between omitting them & risking fouling of lineside equipment.
I'd call triplexes tank locos. Even if you argue the effects of articulation & tender bodies, the handful of triplexes made only had range similar to tank locos, anyways.
I think I have one of those, from Rivarossi in DB black/red.
As far as a Mallet can be, fairly conventional. All the way back on page 1 or so, Mike Edge posted his build of a proposed 'Horwich Mallet.' Not quite a tank, to be sure.
Yeah, those guard irons are going to be a problem if you curve under R3, maybe even R4. Arguably, no fault of Rapido, but of the nature of model railroading.
Getting ahead of myself on this idea.
I may develop the idea of 'Martinson & Co' beyond just this small shoebox layout. I've been having ideas on livery for PO wagons and/or locos.
My question is, would Zinc Chromate ever be used on wood bodies? My thought was a small industry, should it have 'own' stock, might use just a primer coat?
If you want an easier time removing roof equipment, I strongly recommend using a No. 17 X-Acto blade or equivalent. It's a thin chisel. Very useful for shaving off molded-on detail. I've used it before to remove surplus roof vents from an N scale Lima GWR Horsebox. Patient force and a fresh blade inverted left no scarring.