helix or not

[m sharp]

I have designed a new layout for a 12 x 14 foot room. This design has a helix in two places on a doulble-deck layout. The staging area is below. I designed each helix with 24" minimum radius curves and 2-1/2 inch spacing between track centers on each triple helix. I am trying to conserve space with the tight raidii, but I have no choice it seems. Has anyone experienced problems with such structures? I'll go back to the drwing board if I need to.Thanks for your help.
Mike

[randyaj]

With a 24" radius and that spacing you are looking at about a 2% grade, BUT with that tight of a radius you can about double an effective grade to 4% or so in pulling resistance. I had debated a helix on my new layout but decided to compromise my stance and run it twice down a 7' wide center isle. The main drawback of a helix to me was the space that it takes, even at 24" you will need well more than 4' square of space just for each helix and the other was the time that the train would be out of view in the helix, hidden from view. I would rather have a train run only once through one scene but twice is better to me than so much hidden time. So it turns out that about half of my layout is double deck (coming out of the second smaller room and going back into it) and the rest is a two level where the train climbs in view to the height of the second deck.
Just my thoughts
Randy Johnson

[exPalaceDog]

QUOTE: The main drawback of a helix to me was the space that it takes, even at 24" you will need well more than 4' square of space just for each helix

The situation is probably worst then that. The Old Dog would advise placing the helix so that you have access fron at least two OPPOSITE sides. Burying a helix in a corner sounds like an access nightmare to me.

QUOTE: The main drawback of a helix to me was .... and the other was the time that the train would be out of view in the helix, hidden from view.

This might be a hidden advantage. Besides allowing large changes in elevation, a helix could be used to provide the needed distance between stations. Having a engine arrive at station B before the caboose leaves station A is not too realistic.

Have fun

[jwar]

Hi, M Sharp....[#welcome]first of all welcome to the forum.

Using two helixes may be a bit crouded for your room. I have the same sized around the wall layout. My helix is in one corner and double tracked.
If at all possable make the helix as big a radius as possable. remember concerning grades, larger the radius the larger the car height can be if running double stack containers. also the tighter the radius the more drag added to the drag or resistence of the actual grade.

E mail me if you wish....john

[ndbprr]

You have a 12' x 14' room so adding the four walls you have a one lap mianline of slightly less than 52'. If you did a nolix (a spiral around the room) you could have the second level be 12" above the first. So a rise of 12" in 48' is 1" per 4' or 48" and about a 2% grade. You could still have staging below the layout and possibly above the layout and maxiaimze the visible layout. If you think this way consider that the room access is going to be a bit more complicated but once you figure out one layer you can replicate it. MR had an issue in 1978 that had a multilevel railroad that I almost built and might worth a look.

[chateauricher]

I second Ndbprr's suggestion.

I'll be using the no-lix idea to link the 2 decks in my layout. Even in N-scale, a helix would have taken up far too much space in my rather small room. The no-lix allows me to link the two decks while keeping the train visible (and accessible) the entire time. Although you have the option of hiding parts of it in tunnels just so you don't have the train running through the same scene too many times. Mine will be a single track with a passing track about 1/3 of the way up. My minimum radius is 15" on the decks; and 18" for the no-lix.

Other bonuses with no-lixes ...

They are somewhat simpler to build. Since I'm building an "around the walls" layout, my no-lix will run on a series of "shelves". You could hang the shelves at the angle you need to make your grade. Or, do what I plan to do. Hang the shelves horizontally in a series of steps and use WC Inclines to form the grade. Far simpler to do than trying to calculate a 2% grade and hang a shelf at that angle (particularly true if you have corners (like I do)).

You also won't have to worry about headroom or clearance. With a room your size, you'd only have go around your room only once. (I'll be circling my room 2-1/2 times).

[ericboone]

I'm also in favor of the no-lix. I am planning an around the wall with one penisula basement sized layout and have the advantage of the staircase coming into the center of the layout, so no duckunder is necessary. Other than staging, the only significant section of hidden track will be the line that cuts through the utility room (so the track does not have to go in front of the stairs).
The biggest negative for me about a helix was the length of the track that is hidden and the grade required. I am trying to simulate an actual railroad and have the towns spaced appropriately relative to each other so I can use a fast clock and original timetables. The length of the track in the helix would put a town in the helix or have a larger distance than desired between some towns. I am also trying to keep a very gentle 1% grade so I can run long trains and a helix with a 1% grade would have such a large radius, it would take up half the basement.

[TomDiehl]

OK, somebody's calculations are off. You didn't state your scale, so I'll assume HO, since it's my scale. A 24 inch radius helix has a circumference of 150 inches which will give you a 3 inch rise per loop at 2% grade. You also need to allow for the thickness of your track support structure. My club built one several years ago at a minimum 36 inch radius. At 2% grade this gives us about 4-1/2 inch rise per loop, enough room for 2 layers of 1/2 inch plywood for the track support structure. In the calculation, you need to use the minimum vertical clearance (in HO 3 inches for the largest cars), the height of the rail and ties (figure 1/4 inch for code 100 flex track), plus the thickness of the plywood or whatever you're using for the structure. This is where we came up with the 4-1/2 inch figure. I posted some pictures a while back to another inquiry about a helix in this forum, a search may help you find this, or I may need to just email them to you. I still have them in my computer photo album.

Another change you may consider, since these take up so much room (you're talking about a 5 foot square area of your room for each of these) is to go with one helix. The section of the club layout that has the helix is basically an overlapping dogbone, with the helix at the point where the tracks turn back to put the upper loop directly above the lower one.

As far as being out of sight, we didn't enclose ours. Before we had time to enclose it, we had our first show and many of the visitors stopped to watch the trains going up and down. So we decided to leave it open. It's raw framework and track without roadbed and the wires are visible, but nobody seems to mind. As large as it is, you can come up inside the helix.

If you need to see the detail pictures, email me at [e-mail]

[m sharp]

Thanks to all of you for your expert thoughts and advise. I'm now redrawing the plan (HO) with a single helix and trying to minimize the amount of tracks utilizing this helix. The idea of a little larger minimum radius sounds better, even though it will make for a larger helix. That is why I will eliminate a couple of tracks going through it. The no-lix would be possible, but I need to keep one side of the room largely open. Thanks again.
M Sharp

[exPalaceDog]

See August 2005 MR, page 29 upper left advertisement.

www.ro-ro.net

This elevator device is intended for a vertical staging yard serving one level, but one might by able to rework it to serve multiple levels.

Assuming one could convert this into a train elevator, one could put it say on the west wall. Assuming a clockwise movement, level one could be from the North wall, across the East wall, across the South wall, to the elevetor. Level two could be clear around the room back to the elevator. Level three then could be from the elevator, across the North wall, across the East wall and end on the South wall.

Have fun

[Anonymous]

In order to minimize the amount of space a no-lix will cover, consider doubling back on itself, dogbone-style around a mountain or hill. This will increase the amount of rise before you actually start to climb the wall.

Using 2% grades as a standard....

For instance, lets say you climb along a 15' area along the wall, that's 180" X 2"/100" = 3.6" of climb. Now wrap around a mountain with a 60" diameter, which is about another 140" of track (remember the dogbone). This gives you an additional (.02X140) 2.8" of climb. So far you've climbed 6.4" and you've just now reached the wall. By going back around at one wall, and climbing up the other three you could then climb (12+14+12-7' access) = 41 feet more. The total climb would then be 6.4+9.8 = 16.2 inches! This could easily get you up high enough where the duck-under wouldn't be much of a "duck" to get into the room.

Hope this helps.

Mark in Utah

[selector]

I'm out of my depth here....WAIT, I HAVE SOMTHING TO SAY!!!...., but I do understand that helices are huge...no, HUGE...space robbers. Judging from the foreging replies, I am in agreement that you should use one whopper of a helix, as Tom suggests. Two would be highly unsatisfactory after you had gotten them built and tried to run a decent layout, but their dimensions would have led to all sorts of problems, as others have said. Turntables are bad enough, but would you build two of them in the space you have? Not! So, I am glad you are redesigning. You'll have more fun and room with the new design.

[jwar]

Perhaps this may help if your into a helix.
The helix is a space robber if it just a helix, I built my double track helix in a corner (22.5 and 26.5 Rad) and what made mine work great is that I built a track around behind it for my outer lower oval and the inner oval runs in front of the helix, but what is most impressive to me, is that one can get two bridges of good depth of each side of the helix crossing rivers and tracks below.

My base is a 45 degree in that corner of the room. The hardest thing about a helix is not making it look like a volcano, If you decide to build one, take your time, test each level or wrap of the helix before the next level, this is not a place to ru***o compleat and will repay you for your efforts with no problems. Email me if you wish...John

[exPalaceDog]

QUOTE: Originally posted by jwar

Perhaps this may help if your into a helix.
The helix is a space robber if it just a helix, I built my double track helix in a corner (22.5 and 26.5 Rad) and what made mine work great is that I built a track around behind it for my outer lower oval and the inner oval runs in front of the helix, but what is most impressive to me, is that one can get two bridges of good depth of each side of the helix crossing rivers and tracks below.

What do you do when something derails on the back side of the helix?

Have fun

[jwar]

ExPalaceDog
The track behind the helix is not hard to reach to clean track, is a large radius and if it going to behard to reach or unseen track, my advice is to lay excelent track, no derail there yet. Is reachable from inside the helix.

I edited this as when I reread it it sounded a tad grumpy, of which is not my intention at all, Have a goood day...John

[m sharp]

You are all giving me advice that will help in my planning (which I'm still doing). I want the plan to give me everything I want, but I have learned to sacrifice a couple of things to improve the overall appearance of the layout. I have rendered several 3-d drawings and am not totally satisfied yet, but getting close. Thanks for your suggestions.
M Sharp