So in the business of getting the Christmas Tree layout ready, I missed a November posting. But as a concession, the Christmas Tree layout now has ballast on some of the track, ground cover texture, stone/rock coloured cliff faces, dusty snow capped mountains and similarly snow dusted pine trees. Also the wooden base has now been painted to give it a finished look which has highlighted the less finished look of the cardboard sides of the mountains and the very unfinished back of the diorama. So things to do include proper Masonite sides and backing cut to match the scenic profile. Also a better way of ensuring the two halves of the base are brought as close together as possible. Currently there are two possible solutions to bringing together the base halves: adjustable clamps with hooks or threaded rod and washers etc.
But then there are other considerations. After putting some of my longer rolling stock on the diorama, the tight curvature at the two sides really come into play, made worse by the not so well angled or centred tunnel mouths. Tight curvature has many downsides: it looks "wrong", trains are more likely to derail and too tight curves make for hard work if the track guage is not widened to allow for better running. Also about half way round the back of the tunnel the clearance height is actually lower than the portals indicate
And so I come to the word framework in this post's title: as with software, old cars and so on, there comes a time when maintaining the current setup is actually more "expensive" than cutting the ties and starting again. In order to solve some of the main problems with the current diorama, a remake becomes unavoidable. Increasing the radius of the ellipse would require a rework of the track and to do it properly would actually require a new larger base. To fix the tunnel portals would require a reworking of the "mountains" and in combination with the height of the middle section of the tunnel, a rework of the scenery would be required. Adding all the things together should mean a total rebuild.
The down side(s)? The trestle bridge that cost so many nights and and so much balsa and matchsticks would have to be rebuilt. More bridge track may need to be acquired, and would definitely need to be laid, weathered, ballasted and so on. Also some matching coded (height) track for the back section of the diorama that goes through the tunnel. Total re-scenicing would also be required: foam formers, plaster bandage shell, plaster rock facing detail, painting, ground cover, trees, snow...
The question then becomes do the cons out weigh the pros or vice versa? I certainly won't be making any rash decisions until I can attempt to try some of the further fixes like finishing the sides and back and the clamp or threaded rod ideas. After all, the diorama "works": trains go round a Christmas tree, trains go in and out of tunnels in snow capped mountains and over a trestle bridge.
So for posterity, luckily we have cameras to immortalise what will not last forever in any case.