kitpw

I still use gum arabic which is a distinctly old fashioned approach*. (If you can't get on with it, it can always be used up in making marshmallows and [?] other culinary delights). The gum arabic I use as a laminating adhesive for card, paper and blotting paper (excellent stuff as it laps up shellac). Cornellisen (https://www.cornelissen.com) and Jacksons (https://www.jacksonsart.com) stock it and a variety of other exotic resins, gums and varnishes. I use white glue sometimes for shelac'd materials: neither arabic or pva seem to cause them to buckle and wobble. It might be worth a try on some scrap materials to see if either or both suit your methods and preferences. *I was reminded about gum arabic several years ago when reading a 1950s (?) article on making coach sides in several laminated layers of Bristol board. I've tried plasticard but in my hands, it seems to warp, melt, delaminate or otherwise confound my efforts which is why I investigated card and suitable adhesives (with no volatile solvents). The body of the little horsebox I posted about on Swan Hill recently is made from Bristol board, laminated with gum arabic.

4D Modelshop (https://modelshop.co.uk/) - much frequented by architectural modelmakers - has a wide range of sheet materials including ply and very thin MDF (they supplied some 1.5mm MDF to me just the other day). I use quite a lot of ply in various thicknesses and also card and paper: my shellac bill is prodigious as particularly the paper needs toughening up if it is to survive my handling. I do enjoy reading your posts about the devlopment of Traeth Mawr - I might even find out how to pronounce it one of these days (my son just moved to mid Wales and is getting to grips with his local place names) - but I sometimes (mostly, to borrow a well known title) forget to hit the' thumbs up' or 'craftsmanship/clever' buttons. Must remember in future.

Marvellous clip, much to take in there. I did notice the shape of the draw hook shown in close up with the shunter dropping the 3 link: it's not a constant thickness throughout. The part of it that does the work is, as one would expect, pretty chunky but the top/point is slimmed down to make dropping the link easier. A tiny detail on a model but I've found it worthwhile to do the same with the thicker hooks. Thanks for posting the film.

...the shunter's pole may be 7mm to the foot at Swan Hill but the principle is the same - with no other constraints such as different coupling types, then left hand wagon to right hand wagon it is. My initial question seems to have raised some interesting points about coupling technology (to give it a grand title): thanks for all the responses.

Timber for pit props generally came from Canada and, as you say, was usually left "in the round" with bark intact. Timber for headings might be a possbility, (headings: typically 4ft square tunnels for drainage work or similar). The head tree would be 225 x 150 or thereabouts with side trees of 200 x 100 and stretchers (floors) 150 x 100. This lot would produce the rather random selection of timber sizes seen in the photo and they would usually be cut tight to length on site since the tunnel width and height might vary for one reason or another. Equally, they could be for trench work, supporting the sides although I would expect longer lengths than the depth of the SR wagon plus a bit. Although the timber could be for anything, the fact that they are all relatively short lenghts suggests some more particular purpose.

My interest in the couplings is very much to do with how trains start, move and stop and how far that can be represented in model form so your comment pointing out the different behaviour of 3 link and instanter is exactly the sort of difference I've been thinking about although, at the moment, I don't have any instanter couplings on the layout.

True! I've spent a bit of time recently getting the 3 links consistent for thickness of the wire in the bottom link (thin is best), thickness of the hook (again, thin is best) and making sure that the link which goes through the hook is free moving so that it doesn't hang up. Operation has improved: swear box less often required!

No but I have a weaker left eye which may account for the preference! I note that the younger generations in my family are much more adept at using the 3 links than I am and display no preferences for left to right or right to left. Thanks for that, it makes sense to me but then I'm often surprised at what was covered by one rule or another and got to wondering whether I was missing something. Thanks for posting that. I was pretty sure there were some rules about instanter and screw types and the GA confirms requirements where there are different coupling types between vehicles - the rules you draw attention to (2.4 and 3.3) certainly occur in the model and also 1.4 which requires the use of the vehicle coupling when attaching an unfitted vehicle to an engine. This last rule is probably the most commonly encountered in model form and compliance at Swan Hill is rare!

Whilst assembing a train of wagons, I find it easier to lift the link from the left hand wagon and drop it onto the draw hook of the wagon to its right (7mm scale). However, I often find that this convention isn't followed (grandsons etc) and it doesn't make any difference to the performance of the (model) train as far as I can tell. It did occur to me, however, that there may have been a rule about it in prototype practice which I haven't come across - a very minor point which I hesitate to raise but it would be interesting to know!

...and just to think, 300 pages ago, I'd never even heard of a D299.

I think I've understood how the atmospheric railway carriage was engineered to move along the track but the Dawson illustration (feature photo in part 1) seems to show that not all the trackwork was fitted out with the atmospheric tubes. Was it intended to operate the railway as part atmospheric, part steam hauled? It looks as if the tube lying between the rails (in the 7'?) would not interfere with a more conventional loco and carriages: the inability to turn or turnout an atmospheric train would seem to suggest that additional or alternative traction might be desirable.

I've used Photoshop extensively and mainly for combining 3D models (drawn/rendered images) with photos. Where Photoshop is a raster graphics editor, Darktable allows non-destructive post-processing of photos. It has the advantage of being free open source software (Photoshop is now an annual subscription based program) and available for Windows, Linux and MAC. Darktable is an alternative to Lightroom: both have a management capability for organising and archiving large numbers of images. I can't say that I've got to grips with Darktable but there will come a point when I don't want to cough up the annual Photoshop sub and so I've been looking at Darktable as a workable alternative. First though, I need some half-decent photos to work on - something which Nick has kindly helped me with very recently!

@MikeOxon "it was used to carry paperwork and cash in small canisters around a building." ("quote selection" not working) Not just a building: see https://en.wikipedia.org/wiki/Paris_pneumatic_post "The Paris pneumatic post reached its greatest extent in 1934 with 427 kilometres (265 mi) of pneumatic pipes and 130 offices in service". I'll look forward to seeing this model and thread develop.

...nothing! I meant to reference 35236 - not only late but half asleep as well - apologies for that! I think what I was getting at is a comparison between the two wooden underframe (ex-broadgauge?) examples from the Hereford photo, both of which have side and end diagonals meeting at the foot of the corner stud and 16215 which is a narrow gauge van (I assume from new) on a wood underframe which does not. It has the reversed diagonals so not all meeting at the base of the corner stud - thus my thought that this might have been a deliberate development to improve longevity in the wood underframe examples. But I agree that the 'development', if such it was, isn't present in the metal underframe vans and other outside framed vehicles of the same period are a mixed bag - the siphons show a variety of arrangements: diagram 04 is built in a similar way to 16556 and 16215 but there are others which are not. The outside framed goods brake vans aren't really similar enough to make any useful contribution. I don't think there is any structural difference between the two alternatives* so I took to wondering what drove the choice of one arrangement rather than the other? As an afterthought, it's possible that stability of the side door top hinge point is better if the diagonal lands at the top of the framing member to which the hinge is attached since this part of the framing does not have the benfit of the underframe to control the stresses induced in the frame by swinging the door on the hinge. But, as I said, speculation. Kit PW

...late to the party, I only just caught up with your post about the pre-Mink vans. Tavender illustrates 16215 in 'Railway Equipment Drawings', wood underframe, ends that look very similar to the early 4 wheel and 6 wheel siphons and diagonals on the sides running up to the end/corner studs. The illustration on the next page (Tavender) is 35236, with metal underframe, it has the side diagonals in the opposite directon, running up to the corner studs but the end diagonals are the same as 16215, again looking very like the early siphon ends. The diagonal arrangement of 16556 is not consistent with 16215 - from @Chrisbr's list, they were different lots and, presumably, different drawings. As an aside - speculation - The Hereford examples have all the diagonal framing members meeting at the base of the corner stud. That's 4 tenons and holes for the reinforcement plates taken out of the corner stud which itself is (probably) housed into the base plate and all the rainwater runs into this lot, so not ideal. The most one can do to mitigate the weakness is to reverse the end or side diagonals so fewer framing members meet at any one junction - which is what 16215 and 35236 show - making a slight improvement. I don't think this helps your original question Nick but raises some interesting things about design development of rolling stock (in my mind anyway!).

Not exactly a 'just in time' supply chain - as the minutes are dated November 1889, and I assume that the wagon parts were still not to hand on that date, that's some lead time on a March '89 order. I wonder what caused the shortage?

I know very little about DCC but I can see that when planning a layout now, it would be hard not to look at DCC as the way to go - a bit like your move to Scale7 before putting down the first piece of track on the layout. It all looks rather tidy and well thought out which is entirely consistent with the standards you've set yourself, evidenced by the models you've posted on Netherport. And I agree about the meters - I took out digital meters as I couldn't see the need for two places of decimal when I use them mainly for registering shorts/bad track feeds and so on and I didn't much care for the constant twitching of numbers on the panel - the needles describe a rather more sedate progress.

Mikkel, thanks. I hope I've got it right!

Thanks Stephen and for comment about early Clayton carriages (and presumably NPCS). I'd be interested to see what Clayton produced - I did look for other companies' similar dated braking apparatus and there are plenty of diagrams for the general arrangement but with underframes represented by wheels and not much else - no detaill of brakes (mea culpa - most of my library is GWR so I was relying on the web!). It looks like the closest relative in the bicycle world is the 'cantilever brake' with a right angled crank arm each side of the wheel. The "outside link" is provided by the wheel forks. It's an interesting comparison because the brake works across the wheel, not on the circumference, and therefore the blocks tends to rise on the coned rim where Dean's outer brake shoe would tend to move outwards, reducing its efficiency. The coach at Diccot that I referred to above appears (from one photo) to have a bar linking opposite brake shoes on the outer ends of the vehicle which I assume is to counter that tendency. The inner brake shoes are held more firmly in place because their lever arms are anchored to the stub pillars which are themselves linked together. Another interesting thing I noticed with the Dean system on a 6 wheel coach is that the very long pull rods running from the central brake cross shaft to at least as far as the buffer beam show self weight deflection: I haven't seen that with with the shorter pull rods offered by the later system of triangular yokes/tumblers and a single pull rod.

Thanks brossard - yes complex, and yes, RMweb is an amazing rescource (and full marks to those who restored pictures after the great disappearance). In this instance - the Dean era brakes - it was Western Thunder which helped as well. My last post on RMweb about No 88 produced some comments and more photos of 'boxes which sent me off in several very useful direcitons: the comments are always welcome!

I did get some of those from Ambis and they are very nice but, as you say, rather delicate and not up to the twist necessary to turn the rack perpendicular to the vehicle side. I didn't think I could make one - until I tried! Amusingly, it works a bit like a safety pin once the extended bit is cut to length, it can be pinged into a slot in the little stub that holds the lever when parked 'off'. Referring to photos of the real thing, it looks pretty chunky so I thought I could get away with a reasonably heavy material - 0.4mm n/s. Thanks for your kind comment (and for pointing out the anomaly in the initial post: I'm not sure what happened there so I deleted the post and re-did it). It was an effort! - I wondered what I'd got myself into but, on the other hand, I couldn't quite see what I could leave out to simplify things! It became an exploration of the Dean outside link brake which is a bit counter-intuitive in its operation as, on first inspection, it looks as if it couldn't possibly work. Musing on this a while ago, I realised that it works just like an old nutcracker we have which has an "outside link" and cracks nuts very nicely (I included a picture in an earlier post). Once you've seen it, you can't see how it wasn't obvious in the first place: it's a clever piece of engineering and I think unique to the GWR. There were clearly developments in the design either as retro fit or perhaps just on newer vehicles but I think the equipment on the model is a reasonable guess at its date of building. To quote from Monty Python "...and now for something completely different" - perhaps some further building devlopment on the layout.

There are still a few things to add to the model - trumpet vent on the roof (I can't find a drawing and my attempts from photos don't look right) and lamp brackets: I'm sure there should be a groom seated in the end compartment, reading the Racing Post. The challenge with this model has been the braking assembly. I eventually gathered together enough information about the Dean era, outside linked clasp system to make a reasonable stab at it, I don't have an undeframe drawing for this particular vehicle and what is modelled is based on best guess from a set of drawings included in a thread on Western Thunder (https://www.westernthunder.co.uk/threads/v2-4-wheel-parcel-van.10709/) for which I'm hugely grateful, from Great Western Railway Journal No 76 (Autmn 2010) and No 78 (Spring 2011) which carried a two part article by John Lewis "GWR Horse Traffic and Horseboxes": from Russell's "Pictorial Record of GW Coaches" Vol 1 and a couple of photos of GWR 820 Dean Broad Gauge Six-wheel Tricomposite built 1887. Below is my working drawing for the N5 which is a fitted vehcile with a "Dean dustbin" vacuum cyclinder and a handbrake acting on two wheels. The brake action (vacuum brake) works like the nut-cracker I illustrated in an earlier post. Looking at just one wheel, there are two levers with a brake shoe about mid span on each lever. If the inner ends of the two levers (closest to the longitudinal centre line) are pulled closer together, the outside link between the two will ensure that the clasp action will move the brake shoes onto the wheel. Closing the inner ends of the two levers is effected by a single pull rod on the inner end of the outer lever: the pull is provided by a crank arm on the central cross shaft. The inner end of the inner lever arm is fixed to a stub pillar and it's a fixed point so that only one pull rod per wheel is required. The handbrake works in a different way and although the handbrake assembly is also pivoted on the central brake cross shaft, there must be a disconnect between the vacuum and handbrake systems or they would act against each other. The handbrake actuating rods work in compression and are therefore a heavier gauge rod than the vacuum brake pull or tension rods. The central cross shaft is not on the same centre line as the wheel centres and the various actuating rods are not therefore symmetrical - the angle of the rods in side elevation is different for both vacuum and handbrake. Notice also that the lever arms are cranked so that the pull rods don't foul the axles. The Horsebox is almost all scratch built. Wheels, axles and buffers are Slater's as are the coupling hooks and chains. The Brake shoes and lamp housing are from the Broad Gauge Society and decals from Fox. One thing that worked out better than I expected is the brake rack - folded, bent and filed from n/s. As a footnote, for anyone contemplating building this kind of brake, the following is an inventory of just the vacuum and handbrake assemblies: For one wheel:- 1# outside link - 2 x fork ends (drilled 6#): music wire 2# lever arms (drilled 5#): from 0.4mm n/s sheet 1# pull rod - 1 fork end & 1 flat link (drilled 6#): music wire 1# mounting pillar (N/s, turned, threaded 14BA): 14 BA nut 1# strut to mounting pillar (drilled 1#) 0.8mm N/s wire 2# brake shoes (Broad Gauge Soc) 2# brake shoe hangers (drilled 2#) N/s strip Steel pins, heads turned down: fork ends from n/s strip, silver soldered to music wire. Common to all 4 wheels: 2# links between mounting pillars: 1 safety loop (drilled 4#) 2# cross shaft brackets (drilled 2#) central cross shaft: 1 length music wire & brass tube sleeve handbrake actuating lever (drilled 2#) pull rod actuating lever (drilled 2#) 2# vacuum actuating levers (drilled 4#) 1# vacuum cylinder (turrned): 2# fittings to cylinder (drilled 2#) 1# handbrake lever (Slaters) 1# handbrake rack, fabricated from n/s strip 2# handbrake links: 2# fork ends each (drilled 8#): music wire (I think that's a total of 104# 0.4mm drilled holes.)

"the simple answer is just to make some straps and hawsers and hold the tank on with them." @Dave John (quote selection not working (again)). ...which is one of the reasons I started modelling in 7mm/ft rather than 4mm/ft - 1:50 appeals more than either but I intended to mix scratchbuilding with kit building so stuck with 7mm/ft. I did a similar thing with a Slater's twin tank wagon, using short lengths of 14BA threaded road and nuts for both the transverse straps and the inclined ones - I coudn't see how else they'd stay put (and I can't remember now what the instructions said about it). The tank wagon is looking like a tank wagon that could carry a heavy load of liquid stuff - excellent! You're having some fun with 1:50 and it shows in the result.

It looks like a Box Moth. The caterpillars will destroy box trees in no time flat. See https://www.rhs.org.uk/biodiversity/box-tree-caterpillar it is widespread in London and the south east.

It is and I do although not an academic or connected to any institution: I don't think RMweb would count. It's a very useful research resource.