Text below photo I have installed the roadbed for the next level. the left side of the helix goes down. the track there has a 21 inch radius. and I am aiming at matching the ruling grade on the RR which is now a nominal 3.3%. going up to the right the track also has a 21 inch radious as far as the right rear corner of the helix nook, whre the radius reduces to 20 inches. when a tangent off the track up is parralel with the left wall of the helix nook on each of the first two rounds I have added a two inch straight section, so this current level of sub roadbed is three inches out from the center line of the original 21 inch radius circle , This outward creep of the helix is needed to provide clearance for this level and up, as the sloped ceiling of the helix nook is encountered. I'm not 100 % sure this will be enough, I'll have to extend the roadbed to the back wall, and check the clearance. I may have to add a little to the straight section. from here on out, the helix's skew forward will probably have to increase to 3 or 4 inches per loop. I will have to do some mocking up, and carefull measurement. I want the helix to be as far back as possible, retaining enough clearanc against sthe sloped ceiling. I have run into some of the same calculations on my narow gauge shelves, and it is tricky. another turn or two of the helix may be all I can fit up there, as you can see the right side of the helix nook starts to narrow very soon two. that angled 2x6 has metal roofing screwed to the other side of it, so it will not get altered for the sake of the layout. The top of the backdrop will be the bottom of the upper level bench work . the helix won't even get me that hight, so I am going to have to have some lowered thin benchwork to suport the track as it wanders up to the upper level. I don't have that figured out scenicly yet, and that will be a problem. The upper reaches of the center peninsula will be my best oportunity for mountain scenery, so I will want to do it right. there is the danger that it will get crowded up there though, as I will have the mainline rising up and then looping back to the east wall. I need a wye on the main, so I can turn passenger trains, so they can back into State line on the upper deck, Off the one leg of the wye that does not lead to the main line I am going to have a logging branch that goes up to meet the narrow gauge for a log reload. Ideally that should be over in State line near the coal and Iron ore reload, but there is no room. that branch can give ne an excuse for a short section on track with grades steep enough to watrrant my geared power. And on top of those elements the narrow gauge will have to climp from a few inches above the standard gauge main line up to some twenty inches or so higher to match up with the narrow gauge shelf hanfging on the ceiling, so I will have lots of elements to balance.