Is it still a helix??

Model Railroader Layouts and layout building
1

I was wondering, If I was to drop down 8" and having started with a 36’ radius and ending with a 24" radius where the road bed is not directly under each other, sort of like: or more like a spiral. Is it still called a helix?

2

Basically Yes - I would guess it would be best described as a ‘spiral helix’. The big issue would be that 24" radius trackage - very tight for any type of HO climbing helix. You are going to take up enough space for 36" radius anyway - why not use all of it?

Jim

3

Something like this?

Probably still considered to be a helix, or you could call it spirals or loops. A video of a couple of trains on the loops in the link below.

4

That’s pretty much it, except I’ll only have 2 times around, and will be in a mountain.

Thanks, Sam

5

I would call it a spiral or helix.

But the 24" radius may be ok if the trains only go down, but if they are going UP, it will increase your effective grade % tremendously and I would say make it a true helix and have it a the 36" from top to bottom to ease that grade %.

You may find a 24" radius going up to be too steep a grade for your locos to handle. Do a communtiy search for “grade” for some recent posts on grades and %. WHile they may not always refer to a helix or spiral, they do include discussions about curves on grades and how they increase the grade %.

It could be of great concern to you later.