Double Track Helix Question

@BillYo414 posted:

I've been searching for info on the forum on building helixes (helices?) since there's one in my future. Why do I see a recommendation for a double tracked helix all over the place? Nobody seems to really says why you need one but a number of people insist you do. Traffic is the only reason I can see.  Is it that simple?

I'm looking at an 0-72 single tracked helix to travel about 24 inches vertically. The mainline is double tracked but coal drags and passenger service are the only competition I can see for the helix so I feel that double tracking the helix isn't necessary. A train would simply wait until the other passes.

I want to stick to the plan but I know somebody has walked this road before and they might know something that my hubris overlooked.

Susan Deat's layout has Helix's.

I have not built a helix.  The main reason I can see for a double track would be the difficulty in expanding later.  Visually having one going up and one going down at the same time would be impressive.  Sounds like you have a significant plan worked out.

I have @Susan Deats website saved @MartyE haha I have studied her helix work a bit. She's got some clever things going on!

@jhz563 I didn't think of expansion. That's a good point! I won't have much real estate left in the basement for expansion after this though. I also was going to hide my helix. Partially for realism and partially because it will serve as access point and a home for some electronics. Big Boy 4005 had a covered helix similar to what I'm building. His was inside the layout and mine will be concealed by a mountain/coal mine on the layout facing side.

The only reasons I can see for a double-track helix are to be able to go up/down the layout without the need for reversing loops and to save space vs having a 2nd helix. If you just have 1 single-track helix, you need a way to get back to it on both levels, hence the need for reversing loops that might limit your design options,

Beautiful! @DoubleDAZ I have reverse loops covered.

What do you mean by the indexing? @Tom Tee And also the easement. What do you mean by that?

Love the idea of a helix, just can't imagine how I could have fit one in and still had a workshop!

Mine actually fits under the table of the layout. Train goes into the mountain on the top of level and comes out on the lower level. I definitely don't have any space for a helix outside of the layout it would be more convenient but it's not possible.

A helix does not have to be a circle.  It can be oblong thereby allowing smaller curves to a point.  The one in the picture illustrates this idea.  This one was built decades ago and is not a model of good design, but illustrates something other than a circle.

Here's a sample O-72 Helix with a 24" rise and 6" separation done in SCARM. The ovals are offset using 5.5" tracks for clarity and ease of editing.

@DoubleDAZ posted:

Here's a sample O-72 Helix with a 24" rise and 6" separation done in SCARM. The ovals are offset using 5.5" tracks for clarity and ease of editing.

It's easy to draw them in a layout program, it's the building of them that is challenging!

I gotcha @Tom Tee I have plenty of easement built in. I learned not to make a sudden elevation as a kid. No problem.

Bill, here are two reasons my helix is double tracked:  The inside has two sidings for consists.  It's just as easy to build a two track bed in the large space that the 10' diameter outside track required.

The above photo is on my web page, Four Level Track with Helix Access

I think helixes can become a little bit of a bottle neck for operations; especially a single track one. It does take some time to traverse one. I've only seen them on local HO layouts but all of those have been double track. FWIW.   

Jim K

I can see the benefits of the double track. I'm going to see if the track plan can be modified to squeeze a second track on there but the helix is squeezed in there as it is.

Given that my layout focuses on steel mill operations on the top level, the helix is only used to move coal hoppers to and from the mine. But I'm going to be hurting if I want to run mixed freight or passenger service.

@BillYo414 - Have you seen the HO scale Helix platforms for sell on the bay?  I saw one today and immediately thought of you.

I have not. I was planning to just use the wood and threaded rod with nut adjusters. My greatest concern is actually just string-lining the train with a live coal load. That would be damaged equipment AND a mess.

A helix would be super cool, I only wish I had space to do one.

@gunrunnerjohn posted:

A helix would be super cool, I only wish I had space to do one.

You haven't gone down to the floor yet!