I have found it interesting this past year participating in the forum. I assumed that I could learn from others experiences. Not so. I am in full court press mode trying to get my 12' x 10' L-shaped layout ready for the holidays.
I wanted to build the scary mountain, viaduct, North Pole type design for the Polar Express. I designed it using SCARM. I built the mock up and was testing with Remote Thomas as I was waiting for LionChief Polar Express. The spiral mountain is a pain. Well, I was happy because it turned out as designed with a few small mods needed. It has a 3.7-4 degree slope. I have read the warnings of such a steep slope, but tried it anyway. Thomas traveled it just fine. A useful engine, indeed.
Finally, the PE set arrives(3 months late) and I unpack the Berk and take it for a test run. Up the mountain it goes, laboring a little at the preset speed, arrives at the top, crosses over the viaduct section, goes through the 036 switch and around the reversing loop, back over to the mountain and down. Well, the weight of that engine and tender flew down the mountain, stayed on the track, arrived at the bottom turn at grade level and promptly derailed. Too much speed. Try as may to reduce the speed, the momentum increases it to a derail speed. OK. Try an 048 turn at the bottom. Same result.
Much as I wanted to believe a toy train could be different than a prototype, it is not. Physics still applies.
I don't have the time or space to rebuild the spiral to a 2 percent grade. It would be much higher and larger in diameter. The current spiral is about 180 inches of track rising to a 6" height.
Here's some pics- it would have looked nice. It's a removable module that's portable to eventually plop on the Lionel modules. Separate base and mountain.
Lesson learned-do not use steep slopes.