Although it's not obvious from the product list, the 2mm Association kits provide a good start for building GWR cattle wagons - known as MEX (or should that be MEXes?) for identification purposes.
The Association body kit 2-561 is intended for a BR cattle wagon (Diag 1/353) which is very similar to the late GWR cattle wagons of diagram W12. By substituting the Association 2-363 underframe (11'6" DC) for the recommended 2-352 underframe, you can easily build the GWR W8 diagram of 1913 (the underframe kit helpfully includes replacement doors, providing the earlier style of lower horizontal planks, rather than higher vertical ones).
However, I wanted something earlier, so a slightly more radical piece of kit-bashing was required. The following are candidates for my period (1900-1910):
W1, size=large, 1200+ built from 1888 to 1904
W2, size=medium, 300+ built from 1878 to 1982 (outside-framed)
W3, size=small, 99 built in 1888
W5, size=large (but convertible), 575 built 1902-1911
Briefly summarising the later versions, all of which are similar size to W5:
W8, 700 built 1913-1927
W10/W11 300+ built 1923-1928, as W8 but with Morton either-side brakes (ie as BR cattle wagon with GWR doors)
W12 200+ built 1929-1933, as BR cattle wagon
For the purpose of completeness, I should also mention W4, which was the "special" or "pedigree" cattle wagon, fitted to run in passenger trains. Of similar size to the W1 or W5 large cattle wagons, it had louvres at the top instead of open space, and no external bracing on the sides. Vacuum brake gear was similar to fruit and meat vans, and similarly it ran on passenger wheels (3'6" solid instead of 3' spoked ). About 50 were built, from 1888 to 1898. Later versions were larger (about 26 ft long), with a cattle compartment each end and a central attendants' compartment, and formed diagrams W6, W7, W13 and W14, about 50 in total being built.
And finally the missing W9 was for two cattle wagons for the Vale of Rheidol railway.
As cattle traffic moved form rail to road, various cattle wagons became surplus to requirements, and were converted to carry fruit or ale in 1939.
Based on numbers built, and assuming my train is of six wagons, it should probably be something like 4 x W1, 1 x W2, 1 x W5. I haven't yet obtained or built a W2, but will be building a W3 instead.
Simplest to produce in 2mm scale is actually the W5, which is largely similar to the W8. So I started with the 2-561 body and 2-363 underframe, cut out the upper part of the doors and substituted the etched ones from the underframe kit. So far this follows the W8 conversion.
Next came the more challenging parts - the ends require X-shaped flat cross-bracing, instead of L or T-shaped diagonal supports. Perhaps the ends from the early mink body (2-525) could be used instead - but the body is solid, so that would require a lot of cutting and filing.
So I carefully filed off the diagonals from the 2-561 body, (re-)scored planks then added some thin strips of styrene to simulate the cross-bracing. These thin strips are actually square in cross-section, rather than flat bars, so need a little gentle flattening when soft while they are being added. Meanwhile care must be taken to try to avoid leaving various distortions (such as fingerprints) in the softened surface of the ends.
The other significant difference is that the roof is much flatter, so I filed the ends lower/flatter, and decided to discard the plastic roof and replace it with an etched one from 2-336 (actually designed for LMS, but I think they are acceptable for GWR).
Brake gear had various options, DC1 or DC2, with or without vacuum, 8-shoe clasp or 2/4 shoe wagon block style. The one I have built is DC1 with two shoe wagon brakes - which means I should probably snip off the tiebars (which were fitted only to those with vacuum brakes, i.e. DC2).
Two things probably worth mentioning here -
1)From the prototype perspective, this (W5) saw the introduction of the Wright-Marillier locking device which allowed the partitions in the van to be moved - so that the space available could be approximately 18' (large), 15' (medium) or 13' (small) in length. Thus small and medium wagons were no longer needed, and no more were built.
2) From the model perspective, fitting DC brake levers is painfully difficult - the holes in the etched levers are too small for wire to pass through, and too small for any broach I had at the time to pass through. And furthermore there isn't really enough spare metal around the hole to allow it to be safely opened out. The best two suggestions to date are:
i) Use the smallest available broach - nominally 0.4mm, from the 0.4mm to 1.4mm set, instead of the 0.6mm I had at the time (Noel Leaver)
ii) Chop off the end with a hole, and solder the remaining lever direct to the frame (Richard Brummitt)
Fortunately there are plenty of spare levers provided (4 on each GWR DC etch, of which two are needed).
The W1 conversion is similar, but the design predates the introduction of DC brake gear, so there are two plausible options:
1) Use the same underframe style as W5, on the basis that many of the W1 cattle wagons were later updated to DC brake gear (and often fitted with vacuum brakes)
2) Use the intended 2-352 underframe (plus doors from 2-363) to build conventional brakes, with single sided lever.
I intend to have some of each, but primarily in the "old" version with non-DC brakes, as these should probably be the more common in this period.
W2 should be available as an etch from Stuart Bailey - I've not acquired any yet, so they aren't covered here.
Most interesting is the W3 version - although rare, I think I can justify one as an attractive alternative to the W1/W5 large cattle wagons (and not much more work).
For the 8'6" wheelbase underframe I chose the RCH chassis number 2-326, which needs a little filing off the ends to shorten it to 14 ft length. Unfortunately there isn't really enough space available to shorten it, without weakening the fold-down support for DG couplings, so I decided on an additional change - I soldered a single layer of brass etch to the underframe for the headstock, and filed the headstock off the plastic ends - thus reducing length by about a mm each end. For the ends of the body I used the BR cattle wagon kit, with similar filing and rebuilding to obtain cross-bracing.
The sides came from the 1907 RCH 7-plank wagon (2-552), but these needed shortening from 16 ft to 14 ft, by taking about 2mm from each end - which unfortunately meant that the diagonals on the sides no longer run quite to the corners. I cut out the top part of the doors, and glued in replacement doors from another DC underframe etch. Floor was scratchbuilt from styrene - probably as quick to scratchbuild as to shorten either of the existing kit floors.
As is usual with my models at this point, they are "mostly complete" - meaning that roof/body/underframe haven't yet been attached (and need some fettling to fit properly), and though most are painted, the lettering and weathering are still to be done. In particular, the W3 needs some styrene strips added to the sides to represent the various vertical and horizontal framing missing from the upper half. At this point, the horizontal bars are missing from all of them - I have my doubts whether these would be visible at normal viewing range, so I may leave it off. I suspect that to the correct scale they would be about half the diameter of the smallest readily available wire (i.e. about 0.15mm).
In defence of my cavalier cannibalisation of 2-363 underframe etches for the replacement doors, I have identified alternative uses for the rest of these kits. Unfortunately there appear to be no other suitable GWR designs using the 11'6" wheelbase (a failure of Churchward's standardisation policies?). Possibly the Serpents might fit (almost), but the only one that's correct wheelbase is the G8, which dates from about 1870 and had wooden underframes, and only about 20 built, whilst G21 which had DC brakes, albeit on 11 ft wheelbase, was a bit late (1907 to 1913), with only about 30 built. G9 remains a possibility, 11 ft wheelbase and conventional brakes, with about 70 built. But all these have a couple of significant problems - the floor needs lowering, except at the ends, and in most cases the sides (which are about 6 inches high) need some holes drilled in them.
There were numerous North Staffordshire Railway wagons using an 11' to 12' wheelbase and 18' to 19' overall length - not only the obvious cattle wagons, but 2 and 3-plank open wagons. I intend to build some of these later, converting the underframes back to conventional brakes.
Livery and Lettering - I intend the W5 to be grey with 25" lettering, whilst the W1/W3 (and W2 if/when I add it) to be (mostly) GWR red with 5" lettering - possibly cast plates for one or two of the W1s. Not forgetting the liberal application of lime wash, which would probably be seen dribbling down the outside (this stopped around the mid-1920s, when it was banned for potential damage to cattle's hooves).
PS Apologies for quality of photos - I will use lack of sunshine as today's excuse.