GWR Horsebox N4 - part 1
Well, it's been a while since the last post...
It's not that I haven't been doing any modelling, it's just that this horsebox has been a bit of an epic, as you will see. I'll describe the build in three parts:
- the underframe
- the body, including the interior
- the roof and lighting.
It's worth noting that I worked on each of the three sub-assemblies in parallel, so this won't be a completely chronological account of the build, but hopefully it will make the most sense this way.
The starting point is the D&S etched brass kit, which is no longer available, but I was able to find one unbuilt on eBay. The kit is quite an old one, based on hand-drawn artwork rather than CAD, and there are a few issues with it. Nevertheless, it's a good starting point.
The chassis build starts with the floor, bending up the buffer beams:
The kit provides for one axle to be compensated:
The holes for the bearings are too large for Slaters ones, and measurement and testing suggested the axleguards would place the bearings too far apart for the Slaters axles, so I added some washers to pack the bearings out (or rather, in):
The complicated Dean brake gear, with its outside rigging, means I needed to think carefully about the order of assembly, and when things would be painted. I wanted to paint the wheels to simulate the teak centres, and this would be difficult once they were trapped in the axle guard assemblies, so I painted them first and then protected them with Tamiya masking sheet:
The axle guards provided for the fixed end have tabs that look as if they should go into slots in the floor, but there are no slots, and it is unclear how the axle guards should be located. The above picture shows how I made the fixed axle into a separate unit, using spare brass from another etched kit. This was located with a couple of pieces of brass wire acting as locating pins. The pins are soldered to the floor, and the axle guard unit has corresponding holes.
The brake gear is designed to be attached to the rocking unit at one end, and the floor at the fixed axle end. I decided to keep these as separate assemblies for as long as possible, so they could be fully painted before putting everything together. I assembled the brake gear on a sheet of squared paper, sellotaped to a piece of glass:
Incidentally, one GWR drawing of a horse box refers to the compartment end as the 'groom's end' and the other end as the 'kicking end', so I decided to adopt this rather delightful terminology.
The rods for the outside linkages were made up using the wire and etched parts provided in the kit:
I used epoxy glue to attach strips of paper to the brake shoes, to ensure no short circuits:
Next was the vacuum cylinder and associated parts:
A dry assembly tested that everthing would go together. At this stage, everything could still come apart for painting and further work - the rocking axle unit is held in by the pivot rod, which can be slid out, and the fixed axle unit is on its locating pins, which are simply bent over slightly to hold the axle guard assembly in place.
Next were the solebars. The kit provides overlays, half etched to provide rivet head detail. There are also raised areas where the spring j-hangers fit, and also for the small triangular brackets that support the body. However, based on the picture of horsebox number 8 in Russell's GWR Coaches part 1, the kit has the brackets in the wrong place. I decided to file the corresponding raised areas flat:
The prototype has bulb-section solebars, with a top flange and a rounded thicker section at the bottom. The kit doesn't make any provision to represent this, so I tack soldered brass wire to the edge of the kit fret, and filed it to a half-round section:
This was then soldered to the solebar overlays:
They cleaned up to give a nice representation of the bulb solebars:
And here they are attached to the floor assembly:
Another issue with the kit is that on one side the spring stops (etched as part of the solebar) are in the wrong place, and do not align with the centre of the bearing springs. I cut these off and replaced them with a bit of spare etch, in the correct place.
The kit includes whitemetal j-hangers, which I felt didn't capture the look of the original, and would be rather fragile. I decided to bend up my own from brass wire:
The trick with these is to file the wire to half thickness where the circle has to be formed at the bottom of the hanger. I probably should have made some kind of jig, but with a bit of faffing I managed to make eight that were reasonably similar.
The kit has etched steps, but since these stick out a long way they are potentially very vulnerable to damage. I soldered nickel silver wire to the back of the supports and under each step, to add strength. Filed to a rounded profile that is deeper than it is wide, the result is much stronger, while still looking reasonably delicate.
Back to the brake gear, and the pull rods. Two rods need to meet and attach to each end of the double crank. I bent one piece of wire to an angle, so the two could be soldered next to each other, before filing back to a vee shape:
The pull rods were attached to the cranks:
The main chassis component was complete at this stage, with the brake assemblies and axle guard units (complete with wheels) kept as separate parts for painting.
One thing remained - the axle boxes. The kit comes with quite nice grease boxes, which are correct for 'as built' condition, but by my period they should be oil boxes. I used some cast whitemetal boxes from ABS, which needed some modification before they could be soldered to the springs:
The springs are a little thin, so I ended up gluing the spring/axlebox assemblies to a piece of 10 thou black plasticard using thin CA glue, then cutting round them to beef everything up a bit. This helps ensure the springs sit above the ends of the j-hangers as they should, rather than being recessed behind them.
The axleboxes weren't glued on until final assembly, as the springs need to sit above the ends of the j-hangers. The axlebox/spring units had to be be carefully teased into place, as they are also behind the outside brakegear rigging. I realised I had made a mistake at this stage - the strengthened footstep supports clashed with the springs at the groom's end. I ended up cutting the springs into two pieces, with a piece of 10 thou plasticard glued to the back of the two parts to hold them together and to the axle guard. From normal viewing angles, this is pretty much hidden by the steps themselves, but it is just visible if you know what to look for.
I replaced the kit buffers with Slaters sprung ones, but I only attached them at the end of the build. They need to be glued on with the rams and springs already assembled, as there is no room behind the buffer beams to screw on the nuts because of the brake gear.
Vacuum pipes are ABS (nicer than the kit ones) and steam heating pipes are brass castings from CPL, as are the screw couplings.
You'll see the underframe painted and assembled in the final part of this build, but in the meantime, here is a taste of where we are heading:
Next time - the body.
Nick.
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