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Latest Status - 25 June 2021
All of the major components to start the assembly of the dragbox area are now in stock and are awaiting assembly. The outstanding items to procure are the rear firebox supports, the trailing truck pivot pin and the trailing truck centring pin.
After completing the bogie frame (phase 1) our plan is to assemble the components that sit around the dragbox at the rear of the frames.
The dragbox is situated at the rear of the frame extensions and is the brown component you can see sitting between the 2 blue frame extensions (click image for a full size view). The vertical hole is where a large pin is located that engages with the locomotive/tender drawbar. The dragbox is in stock and will be fitted, together with the frame extensions. We expect that work will commence in this area shortly./ Fitted to the rear of the dragbox is the hind beam. Gussets (yellow and green) strengthen the ends of the hind beam and allow the weight of the rear of the locomotive to be transferred to the trailing truck frame. On the rear face of the hind beam is the central intermediate rubbing block. On each side of this are the 2 rubbing plates. All 3 components have manganese steel rubbing plates on the rear surfaces to minimise wear. On the bottom face of the gusset is the pony truck bolster. This is a plate with a dome facing downwards which engages in a bolster cup which is free to "float" on the oval plate on top of the pony truck frame.
This is a rear view of 70000 Britannia's hind beam when under overhaul. The class 7 Britannia frame assembly is very similar to class 6. Thanks to Nigel Fraser Ker for allowing us to reproduce this photo. This shows the central intermediate rubbing plate, the outer rubbing plates and the pony truck bolsters fixed to the gussets. The frame assembly is sitting on a temporary truck.
The next stage in frame assembly will be to
- Check the hind beam plate that we have in stock, drill fixing holes if required and attach to dragbox
- Check the 2 large rubbing plates that we have in stock, drill fixing holes if required and attach to the rear face of the hind beam
- Fit the 2 manganese steel liners that fix to the face of the rubbing plates, this requires some welding
- Fit the intermediate rubbing block that sits between the 2 rubbing plates and is attached to the hind beam
- Fit the 2 large gussets that sit either side of the frame extensions bolted to the hind beam
- Fit the pony truck bolsters
- Manufacture the Rear Firebox Supports
- Manufacture the trailing truck pivot pin and fit this to the front firebox support stretcher
- Manufacture the trailing truck centring pin and fit this to the dragbox.
All of the specialised fasteners are in stock.