The first of the two big inclines on this model is now complete...
The picture shows the finished double-track bed for the feeder tracks, with the final running height at top board level. Most of the bed on boards F3 and F4 will be "above ground" in the final model; the tunnel portal will be somewhere at the right-hand side of F4.
At both ends of the incline I have tried to ensure that there is a smooth transition from gradient to level; the upper transition happens in the middle of F3 (looking at the photo, it seems that it may still need a bit of adjustment). I certainly want to avoid changes of gradient at the edges of the boards at all costs, as here the track will be discontinuous as well.
The feeder track beds are made from 6mm MDF (the remnants of my old table-top layout) braced underneath with battens to increase rigidity. Because the top material is 6mm grade rather than 9mm, I have added an extra 3mm of height to the supports at top board level, to ensure that the surface levels align when the 6mm MDF meets the 9mm plywood further round the loop. As I've gone round I have also been adding extra front-to-back battens to F3 and F4, to provide extra strength and make it easier to attach the track bed supports.
I am pleased with recent progress and am looking forward to completing the loop round to the station approach on B1u. Next comes F2 and a bridge over a river!