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Helix's with incorporated turnouts

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  • Member since
    October 2005
  • From: Northern Va
  • 64 posts
Helix's with incorporated turnouts
Posted by rclarkdc on Saturday, August 29, 2009 10:10 PM

 I am in process of figuring out what to put into a 10x20 room I will inherit in a few weeks.  It seems to get smaller every time I contemplate 85' passenger cars, which are a "must" unless I rethink everything.

Double decks for part of the run would also be nice. To that end, I am trying out layout designs which would have one grand helix with three incorporated turnouts.  Two of the turnouts would enable the helix to double as a reversing loop, and the third would accommodate a middle yard/terminal level which I need in order to keep grades under 3%.

I do have a way of gaining access to two opposite sides of the helix, so I think maintenance will be reasonable when required. 

 My question right now is a simple one.  Have folks had success with helixes incorporating turnouts in their run, or am I just begging for trouble if I do this.

Appreciating all help

 Bob

  • Member since
    April 2007
  • From: Ontario
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Posted by da_kraut on Sunday, August 30, 2009 7:07 AM

 Hi,

on my pull out track from the yard I installed a turn out.  This turn out is on a half loop down that is about 3% of grade.   This loop is 30 inch radius.  I installed a #6 Atlas turn out and it seems to work well.  I can push and pull 12 car consists through it without any worries.  Would I install a turn out on the other 6 loops of the upper helix, no.  I believe that it would cause derailments when pulling up or descending with a 30 car freight. 

Hope it helpsSmile

Frank

PS:  There is this great layout in my area, here is their web site http://www.wrmrc.ca/ .  They have turnouts at the top and bottom of a helix but not in the middle, at least from what I can remember.  They are the authority on helix's so maybe ask them.  

"If you need a helping hand, you'll find one at the end of your arm."

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Posted by Allegheny2-6-6-6 on Sunday, August 30, 2009 11:41 AM

 When we built the helix for my friends layout we copied almost exactly what Cliff Powers had done with his layout ( now 3 levels) we had thought about using a turnout for each level but both agreed that getting smooth operation in a helix is enough of a challenge so why throw turnouts into the mix to complicate things which would have to be curved turnouts as well. So what we finally decided on and it seems to be working very well is that we actually split the helix in two. You run from level one to level two and out onto the main and make the circuit back to the helix and then continue up to level 3. You can not take a train directly from level 1 to level 3. Once on any particular level your train can remain there as each section are continuous loops. The main line on all three levels are pretty much identical with some minor variations. He is doing this in a 35x45' basement so he has a massive amount of mainline running. The helix does take up a 6' square section which doesn't sound like a lot until you see it. The helxi took months of preparation and planning and a weekend to build.

Just my 2 cents worth, I spent the rest on trains. If you choked a Smurf what color would he turn?
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Posted by trainnut1250 on Sunday, August 30, 2009 12:42 PM

Allegheny2-6-6-6

 split the helix in two. You run from level one to level two and out onto the main and make the circuit back to the helix and then continue up to level 3. You can not take a train directly from level 1 to level 3.

Very similar to my design.  I would not bury turnouts in a helix as they will be very hard ro repair or replace if they become a problem.  I have turnouts at the entrance and on top level of my helix, but not buried inside it.  I also opted to split my helix into two sections as described above..

 

Guy

see stuff at: the Willoughby Line Site

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Posted by tomikawaTT on Sunday, August 30, 2009 2:29 PM

Caveats:

  1. I hand-lay all my specialwork, so odd radii, curved turnouts or even a double slip as part of a helix would hardly stretch my tracklaying 'muscles.'
  2. The closest I come to a helix, approximately 540 degrees of 350mm radius on a 3.5% grade, 1:80 scale, 16.5mm gauge, does not need and will not get any turnouts built on it.

Putting a turnout on a helix should be no big thing as long as the turnout is 'flat,' i.e., built with no grade transition until well clear of the frog.  Putting a turnout on a helix is no different from putting it on a grade on a tangent.  At the worst, you might want to install a guard rail to guide flanges away from the outside-of-the-curve point.  (I have done this on a curved turnout on the flat - cheap derailment insurance where it would be awkward to have one.)

Chuck (Modeling Central Japan in September, 1964 - with lots of turnouts in strange places)

  • Member since
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  • From: Westcentral Pennsylvania (Johnstown)
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Posted by tgindy on Sunday, August 30, 2009 5:50 PM

tomikawaTT
Putting a turnout on a helix should be no big thing as long as the turnout is 'flat,' i.e., built with no grade transition until well clear of the frog.

The above flat-surface turnout insight is sound advice!

Still thinking about adding a "third level" dedicated for staging to the multi-level CR&T with an oval-shaped helix which will reduce the grade and coupler-tension.  Occassional rerailers are planned as a derailment safeguard on the helix straight sections.

Helix accessibility & visibility are critical, and turnouts add complexity.

The CR&T helix will have 2-tracks, and perhaps a third track, but; consideration is still there to design additional staging with access from the top level only to the staging level -- in effect more than 2 tracks (likely outer tracks) for only part of the helix.  So, there may be no need for any helix turnouts.

See the Guide to helix and staging design cover photo turnout locations.

 

Conemaugh Road & Traction circa 1956

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  • From: Mississippi
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Posted by maandg on Sunday, August 30, 2009 7:55 PM

Allegheny2-6-6-6

 When we built the helix for my friends layout we copied almost exactly what Cliff Powers had done with his layout

As mentioned, my MA&G incorporates a double track helix which serves three levels. The lowest level is 30 inches from the floor and has staging for 30 trains. The second level, at 40 inches, represents the rural mainline run south of Hattiesburg, MS to the fictional town of Edna, MS. The upper level is 57 inches and entirely represents New Orleans.  “Bridges” made from 2 x 4’s span the doorway and connect the helix to the layout eastbound.  The opposite side of the helix exits across or above my desk westbound.  These photos will help identify these areas. 

These were my design dilemmas.......

When MA&G/Southern/GM&O trains leave staging over shared trackage, they take the OUTSIDE track of the helix, traverse 3 laps, then exit on the second level. After making the run over the second level, they re-enter the helix at the same point they left by way of a strategically placed 30 degree crossing (the helix briefly levels out at that point). The trains then negotiate 5 more laps until they enter the third level. You will also notice in the photos that I made provisions for continuous running on all three levels independent of each other.  This is because the layout was completed one level at a time beginning with the lower level. I was always able to enjoy just running trains while construction was underway on the next level.  These "continuous running" tracks will not be used during Op Sessions, however.

Because I model the New Orleans Union Passenger Terminal, I needed a way for all of the foreign road passenger trains (SP, MP, T&P, KCS, IC, GM&O, L&N and Southern) to go from staging DIRECTLY to the third level. That's where the inside track of the helix comes into play. This track bypasses the second level entirely, preventing these other trains from traveling over the MA&G mainline. I thought it was a pretty cool idea.

This photo should help clarify my track design.

For me, the helix represents the un-modeled mainline between rural Edna, MS and urban New Orleans.  This is the largest distance in terms of scale miles traversed between towns.  Also, much of the run in the helix would have been over water and swamps.  The helix represents this transitional time warp beautifully.  While it may not be the most exciting part of the run for operators, it does create distance and visual separation between modeled areas. Since the 5 laps only require about 2.5 minutes of real time, it's not a big deal in my mind.

Another point I want to make is that because of the relatively flat topography of the area I'm modeling, an around the room grade was unreasonable.  Because of this, I prefer to have my trains restrict climbs to an isolated helix and keep the layout perfectly flat GRADE-WISE.  I use hills and cuts to eliminate the ping-pong table effect. Most of the responses I have gotten from my website mention how much it really looks like the area I'm modeling. A grade would have ruined this effect.

I really like my helix and have had no problems with it whatsoever. It was quite a construction chore, but it went together easily. The helix is built from 1/2-inch plywood and takes up a space 6-feet square. The outside track has a radius of 34 inches and the inside track has a 31 inch radius. The inside radius of the plywood is 29 inches and the outside is 36. There is a 3-inch clearance between the levels which are separated by wooden spacer blocks I cut on a miter saw. The grade in the helix is 1.63% for the outside (34") track and 1.79% for the inside (31") track.  Not bad at all.  Once you get the first loop built, it is a simple matter of using the spacers to build off of it. 

This shot of the interior of the helix will illustrate the construction techniques.

The worst part was cutting the arches from the plywood with a jigsaw.  I cut 2 half-moon segments from one piece of 4x8 plywood, thus yielding 1 complete lap per sheet of plywood. To join the sections, I used the same trim pieces I used to make the spacer blocks as splice plates. These were secured with carpenter's glue which was clamped overnight to dry. This method was also used to secure the supports in place. It will probably come as a shock, but I have no wiring in the helix. When I built the helix, I planned on staying with DC and didn't run any jumper wires to a bus. All of the joints on the sections of flex track are soldered, so I only have jumper wires to the very bottom and very top of the helix. Even though there is nearly 300 feet of trackage in the helix (double tracks), I have never experienced any continuity problems - even once I switched to DCC. Now that the helix is built, there is no way to have access to add a bus wire even if I wanted to. But I have found that to be unnecessary.

Here are photos of my helix before and after I added a Masonite fascia.  It created a “Window Box” effect which I like very much. 

The flat turnouts "in" the helix have worked flawlessly for 9 years.  I hope this information was helpful!

Cliff Powers

www.magnoliaroute.com

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Posted by cv_acr on Monday, August 31, 2009 12:17 PM

At our club we have a lot of hidden track and helixes and we have avoided putting any switches, crossings or other special track in any hidden sections (except directly in the staging yards).

A well-built switch will usually not cause any problems, but murphy's law says the switch you can't access will be the one that gives you issues. Plus having a hidden switch or crossing is just asking for trouble operationally due to human error if a switch gets run through backwards causing a difficult to access derailment, or if two hidden lines cross it's a definate invitation for two trains to hit each other.

  • Member since
    May 2005
  • From: Westcentral Pennsylvania (Johnstown)
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Posted by tgindy on Monday, August 31, 2009 1:53 PM

maandg

 

When MA&G/Southern/GM&O trains leave staging over shared trackage, they take the OUTSIDE track of the helix, traverse 3 laps, then exit on the second level. After making the run over the second level, they re-enter the helix at the same point they left by way of a strategically placed 30 degree crossing (the helix briefly levels out at that point). The trains then negotiate 5 more laps until they enter the third level. You will also notice in the photos that I made provisions for continuous running on all three levels independent of each other.  This is because the layout was completed one level at a time beginning with the lower level. I was always able to enjoy just running trains while construction was underway on the next level.  These "continuous running" tracks will not be used during Op Sessions, however.

For me, the helix represents the un-modeled mainline between rural Edna, MS and urban New Orleans.  This is the largest distance in terms of scale miles traversed between towns.

Thank you Cliff.  It looks like the CR&T "is thinking" in the right design direction, including your concept, of the unmodeled mainline.  Your helix pioneering examples, let alone pictures above, are greatly appreciated!

Conemaugh Road & Traction circa 1956

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