While I had a good day today, I made a huge mess in the basement. I spent all afternoon working on benchwork for my yard. While I was cutting half-laps on the radial arm saw my mind wandered a little bit (but not too much since I still have all of my digits!) and I wondered how does a structure for a lineside industry get added if using spline roadbed? Add the siding itself seems like more of the same as making the rest of the roadbed, but then what? Add a small piece of plywood/OSB/foam board/whatever supported from the benchwork just like it was a part of the track, or is there some better and easier method? I am still early enough in the building process to change things pretty easily bit want to plan ahead as much as possible. I know there will be a number of industries added as I flesh out the rest of my plan, but right now the only thing accounted for will be right next to the yard!
Good Luck, Morpar
What I would do is splay out, curved back parallel, the outer two splines when you get the roadbed to the turnout. So, two splines will deviate wide and then turn back onto either a wider riser or a second riser. If you follow.
Then, continue the main placing splines numbering how many you have been using, butted up as tightly as you can to the splaye ones. Shape them to get a tight fit if you wish, but I just wadded up toilet paper to fill gaps, or use masking tape. You don't need anything more elaborate.
Similarly, where you splayed wide, inboard of those two you add more splines to get the width of the roadbed that you want (or sub-roadbed if you're going to use cork. I didn't bother.).
I hope all that makes sense.
As for adding a surface to mount something like a structure, you could glue a lower plate of plywood to the underside of the splines, and then fill with wood remnants of a suitable size until you are very close to grade for the siding. Or, using yet another riser or two, if you have the room, affix a piece of 1/4" plywood there suitably sized for you needs.