Frame Assembly Phase 2
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For most of the photos on this page, you can click the image for a larger picture.
Once the bogie has been completed we intend to turn to the rear end of the frames for frame assembly phase 2. This is where we will assemble the components attached around the dragbox at the back of the frame extensions. The dragbox and frame extensions will be fitted in Frame Assembly Phase 1.
The class 7 Britannia frame assembly is very similar to class 6. Thanks to Nigel Fraser Ker for allowing us to reproduce this photo.
Ignore the truck in the lower half of the photo.
At the top of the photo is the hind beam totally obscured by other components fitted to it. In the centre is the intermediate rubbing block which has 2 manganese steel liners on the top and bottom curved faces. This connects to a similar plate on the tender. Either side of the central plate are 2 rubbing plates. Intermediate buffers on the front face of the tender press on these plates. The buffers were introduced as a result of early problems on the Britannias with a periodic surging when braking or the regulator was eased at speed. See Bill Harvey's book "60 Years in Steam" for details. Under the intermediate rubbing block in the centre you can see the protrusion from the dragbox with holds the pony truck centring pin. Underneath the outer rubbing plates you can see the gusset castings that strengthen the back corner of the frames and hind beam. Underneath the gussets are the domed bolsters that will engage with bolster cups on the pony truck.