My Thomas trains are huge crowd-pleasers when my Ntrak club sets up at shows. Trouble is, they're 8" long and still require two blocks, same as longer, prototypical trains. I had the idea to make a "canyon module" with a viaduct at normal height, and run Thomas and friends on an oval in the valley below, at a height better for the small children. With a tunnel, of course. But before I started chopping up expensive lumber and plywood, I needed to see if it would work. So I built a 1/4 scale model of the module using balsa wood and cardboard. It won't work. At least not as visualized. I had about an 8" drop planned, to really put things at eye level for the kids. Well, the mockup shows me I was too ambitious. To get from the valley floor to the mountain line is darn near a cliff, not the rolling green hills of an English vale. All the drawings in the world just can't compare to 3D. Maybe a 3 or 4" drop will work. Next step is to look at some of those European brick viaduct kits. It would save a lot of scratchbuilding. And start collecting cardboard again for the next try. I recommend this to anyone trying something different. It's good practice and it saved me a lot of money.
Don't know how you had it laid out, but would something like this work? If the whole thing was 48", allow 2" on either end for structure (not drawn), the light green slopes could be 45 degrees (still quite steep, but hey!) at 8", and you'd have 28 inches of level ground for the Thomas oval below. Put one or both curves of the oval in a tunnel inside one of the slopes and the lower track could be a bit bigger. The effect would be as though you were looking down a long valley between two parallel ridges, with the viaduct crossing from ridge to ridge. Quite common in the Appalachians, at least... You could level out part of the slope by modeling the upper 1-3 inches of the rise as either bridge abutment or a vertical rock outcropping. a 3 inch (40 scale foot) cliff would get the slope below it closer to 30 degrees while still eating only 8 inches horizontally...
We use Thomas and his friens as "kid magnets" on our Ntrak layout too plus playing Thomas DVD's at the drive-in theater. Back to your dilemma, could you have two separate loops for Thomas to run on? The lower one as you described and a higher one crossing the viaduct. A member of our club had come up with a very similar scheme since he brings all of the Thomas trains (he's also put DCC in all of the locos) to run on our mountain (green) division. Regards, Al Evans UNW Ntrak Division
Twin Dad: That's pretty much what I had, except the valley was U-shaped, and the tunnel goes under it. It's complicated by using the alternate blue line to line up with the club modules, and adding the mountain line. My idea still works, but I just can't have as deep a valley.
