O72 helix

Assuming O72 curve for the entire helix, and 6" vertical clearance between levels, you'd need 8 loops to make the 48" change in elevation.   The 6" clearance per loop will result in about a 2.6% grade. 

 

A 5" vertical clearance would reduce the grade to about 2.2%, and add another roughly 1.5 loops to achieve 48" change.  A 5" clearance is going to rule out certain types of tall equipement.  (Be careful on this one!...I ended up dumping a whole collection of a particular car type because I had missed this just on bridge/tunnel clearances!!) 

 

We (LHS) advise layout planning customers to try not to exceed 2% grade as a general rule.  As has been voiced on this forum so many times, the steeper the grade...ESPECIALLY on curves...the greater the reduction in pulling power of your equipment. 

 

BTW, going back to the 6" example the circumference of each loop is about  226", or roughly 18.8 feet.  Ergo, your total helix for the 48" change (8 loops) would require a run of 150.4'.  Another perspective: Using Lionel FasTrack...16 pieces of O72 per circle...it would require 128 pieces of track to complete the helix.  At a full retail of $7.49 per piece, that would run about $959..."plus tax".  But, hey, if you want to buy that much, we for sure would reduce that $$$ significantly...as would most accommodating LHS's.  O72 tubular track would be somewhat less costly, of course.

 

Of course, building a viable helix substructure is an engineering and budgetary challenge in itself.  There are commercially available kits to do so and undoubtedly take a lot of the guess-work out of the process. 

 

Sounds like an awesome task.  Be sure to keep us posted with pics if you proceed.

 

And....Good Luck!!

 

KD

Tubular would be the way to go but not thousand dollars for track for a helix is a lil much. I wonder how much tubular track would be? May have to rethink this

Also consider the thickness of the track itself, the roadbed and helix cross members for your clearances. Six inches rail-head to rail-head only means about five inches of actual clearance with 1/2" plywood. Using nickel angle brackets supported by side columns to support the track would work to provide more clearance, but the construction is more complicated.

Here is extensive information that I have collected in the past.

Helix Design

 

My first layout helix was 7' diameter Lionel tubular track.

 

Here's one that I'm building. The inside track is 84" diameter and the outer track is 92". Each turn rises 8". That's about 3% on the inner track and a little over 2.5% on the outer.

 

Sorry...I should've added this in my original reply.

 

Tubular O72 would run about $805 MSRP..."plus tax"... in the same example.  Again, most LHS's (like us) would/should give a fairly decent break on a purchase of that sort.

 

Still.....as has been suggested, it's a fairly expensive 'elevator'.

 

KD

A helix is a long run of track with little or no scenery potential. It would be more interesting if the track could be configured as a long visible zig-zag climb ascending a mountainside. Approximately parallel tracks at different levels on a mountainside could be done on a reasonably narrow table between the turn-back curves. That way the track could be a major scenic and operating feature of the layout. The Cascade Line in Oregon has a section with three tracks at different levels in a valley on a long ascent to the summit.

Ace, that's lovely, but it doesn't really address the OP's criteria, especially in the height department. He wants to gain 48" total height. We don't know if he even has 20' to donate to the scenic version. He also specificly stated 072 curves, perhaps he has large steam engines.

 

Then there's the matter of cost. It can be done for far less than $1000. Consider using Gargraves track. At slightly less than $6.50 per 3' section (shipped), it will take about a case (50 pieces) to do a six turn, 8" rise per turn, helix. At 072, that puts the grade at just about 3.5%. While not optimal, that is within the realm of do-ability. It just means you'll need to adjust your train length, or add another engine. Keep in mind that the Lionel graduated trestle set, when used as directed, has a grade around 6%.

 

Then there's the matter of structure. I use a very lumber intensive construction method, and estimate my cost to be around $500. I know it can be done with a lot less material and less expense.

 

I've never tried the threaded rod method, but I've seen them, and it works great. Use 1/2" plywood for the roadbed. Guessing a cost of around $300 for materials. Add the track at $350 for a total project cost of around $650. That sure beats $805 for the track alone.

I'm going to use the whole room as the helix. It is a 12x10 and I should be able to get the incline/decline that way to layout level. Thanks for all the replies.

This is also known as a "nolix" plan which is common for multideck designs for the smaller scales without having a space/distance/time-hogging helix. Unless the layout is really large, there can be more mainline in the helix than on the rest of the layout which means the trains spend more time in the helix than elsewhere which throws proportions off. This is one of the reasons why helixes are commonly built with two tracks to avoid creating a bottleneck.

 

Peter

 

What are you doing, jumping from one brainstorm to another?

Just trying to figure how to get my two main loops ie living room and bedroom down to my layout. Coining around the layout room once will bring to the top level of my layout. I thought by doing a helix maybe easier plus I was going to disguise the helix around a volcano type mountain. Thanks for all if the advice.

Here is a nifty space-saving idea for you:

 

Vertical Transfer Table