I laid out the next section of mainline last weekend. The aim was to get past the crossover, but I ended up going beyond the trestle.
I got to thinking about how to build roadbed over the trestle. It’s on a compound curve, but a constant 1% grade. After a bit of pondering I decided to start there and work backwards. I used a spline as this needs to stand alone with minimal support till the trestle happens.
The conduit had to stay in place while I build around it. I cut some blocks the same width as the centre spline + 2 spacers, then drilled a hole to fit the conduit then set them out every 600 mm. Trestle length worked out to be about 2.5m between the frame ends
Then it was sorta straightforward to build up 2 runners on each side. The baking paper is supposed to stop the spline gluing itself the the suports, fingers crossed it works…
I made sure the runners were staggered at the ends so there wouldn’t be a bunch of joins in 1 spot. Ultimate test was pulling the conduit out…
Plan is to build the trestle around this structure some time in the future. Apologies to the purists, the curved outer stringer will be seen!