Alright, I’ve never made a helix, or even seen one in person.
Here is a sketch of a layout I’m thinking about - it’s two 2ft x 8ft sections, connected by a helix. It’s point to point.
One “module” will be a yard, the other will be a “destination city”, etc.
The “land between the two end points” will be represented by a helix.
The helix curves, as well as the curves leading into it, have a radius of 21.5 inches.
The helix climbs 3.5 inches with every turn. This gives a roadbed plus track thickness of 1/2 inch, and a vertical clearance of 3" (which is what my NMRA HO gauge measures at.
This gives me a 2.6% grade.
So, the big question is, can trains go on a 2.6% grade on a 21.5 inch radius?
I’d like to run 3 axle diesels and 50ft freight cars.
Any advice?
I do realize there’s that S-curve going into the helix, but there’s nothing I could do about it at the moment.
Personally, I think you’d be much happier with two unconnected decks joined to separate staging yards, linked by an operating concept and staging. I’ve written about this in a few places and designed a few layouts using the concept, and it works really well.
The two stacked staging areas can represent the same place or different locations.
That 2.6% grade will seem like a lot more to the train, since it will also be pulling against the drag of the tight curves. You might also check your tallest rolling stock vs. the NMRA gauge. More modern cars are taller than the “classic” NMRA gauge.
If that’s all the room you have to work with, I’ll be dammed if I wouldn’t run short, 4 wheel locos like crittere and 4 wheel rolling stock. You could turn them around in less than 2’, and not have to worry about a helix.
Perhaps flipping the upper and lower track of the helix, is easier to build the upper support
Then try somhow to get a straight section in the S turn.
I dont use cork in my helix, in my personal openion it doesent do anything but take up needed height, reduce the grade, is also the start of a slippery slope if a bad derailment occurs
I would take the box layout back to the wall and include the curves ion the layout., could use curved turnouts if you need a longer yard.
Be sure your future six wheel locomotive are not 22 R min,
Just my two cents…John
I looked at the diagram and WOW, 6 layers of track to go up a short didstance, I tried to figure another circle system, then I thought, there HAS to be another method of models going from one level to another, 6 large circles of track is a long distance and a lot of track ! NOW the solution, switchbacks?? 2% around the box?? underneath helix?? underneath 2% long returns?? elevators?? wow, this is quite a problem, just how can you get the train from one box to another economically, surely out there we have some engineers that can solve the problem, this is simply a physics problem, now off to the drawing board.
Any way you could increase the radius to 30"? That would take you down to just over 2% grade with a 4 inch rise, and relieves some of the drag of the tight curve. Also keep in mind, you will have to connect the wooden sections of the helix together somehow, usually on the underside with another piece of wood. Take that into account when calculating how much rise you want to accomplish in a turn (thats why I said 4").
