The coal rails are simply 2 lengths of 0.3mm straight brass wire that were taped down while narrow strips of 0.004" nickel silver were soldered across them centrally and about 11mm either side of the centre line for the support brackets. Once the brackets had been soldered on and cleaned up, the bunker rails were bent to shape to fit around the bunker and the ends of the two rails bent downward in characteristic fashion (the support brackets were soldered in place with 188 degree solder so that I could subsequently attach the assembly around the top of the bunker with 145 without the risk of it all dropping to apart to its constituent pieces).
The lap sockets (rather than brackets - the GWR used lamps with a square spigot projecting below the case that slotted into a square socket about 4" square with a central square hole to accept the spigot in the early 1900's, on the bunker back these sockets were mounted on a "stalk" that projected from the bunker back) were formed from 1mm diameter brass rod by filing a square section on the end of the rod, and the rod filed down in a mini drill to represent the "stalk". Once made each was soldered in place in holes in the bunker back.
The handrails are simply made from 0.008" guitar string (the handrails were polished steel in the early 1900's), with knobs made by taking short lengths of 0.2mm copper strand wire (a single core from multi-core wire), forming into a loop the tails of which were trapped in a pin chuck, the guitar wire was passed through the loop and the chuck spun until the loop wire snapped off. This results in a twist of wire with a small loop on the end that when soldered in place forms a neat knob.
The fire iron hooks are again simply made (but the very devil to solder in place) from narrow strips of 0.004" nickel silver bent into the characteristic shape.
The close up photography below shows that I still have some cleaning up to do and the projection of the top of the handrail above the knob on the left hand side needs filing down a little.
A set of small turnings that won't be added until the painting is complete are the things that are are part of the leading springs that are fixed below the footplate valance (shown clearly in the photo below)
Because they are polished steel, these have been turned from 1.5mm silver steel rod - the fattest part is 1mm diameter, the spigot below and the stalk that I've left on to allow them to be blued behind the valance and considerably thinner!
Finally, I've made the tool boxes and the tank fillers. The tool boxes are simply 3mm square brass with one side filed over to give the rounded top, a slip of 0.004" nickel silver being rolled to shape and soldered onto this rounded over part to represent the lid, the embryonic lid was filed back to be just proud of the sides of the tool box. The tank fillers are again small turnings, the clasp to keep them shut being made from 0.008" nickel silver soldered into a slot sawn across the diameter of the lid and filed to shape once soldered in place.
Also shown in the above photo is the brake standard that goes inside the bunker. The bunker has been filled with lead and a hole drill into it to accept the bottom of the brake standard. The finished article can be seen in place in the photo below.
The next stage is to make the smokebox front and fit the boiler handrails - then unless I spot anything else that I ought to add she will be ready for a coat of paint :-)
Edited to add further photo with all of the bits plonked on to give an indication of how she's looking now :