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Does a helix ever really work?


Harlequin
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Hornby Magazine featured a helix built railway in their October 2016 issue. The layout was built by Chris Jones ~ oh he of "The Corkscrew Lines" hall of fame. If you have never come across "Corky" as he is known, then you have really missed some good blog entertainment!

 

Whilst his blog posting finished at the time of the Hornby Magazine article, both the Mk1 and Mk2 layouts he built during his blog posts are still available to read and well worth while. Let him introduce himself, and then continue to his blog pages.

 

The helix he built featured a magnetic underlay to aid adhesion, which has to be installed prior to laying any trackwork.

 

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Actually I meant camber, not banking. Im not a professionnal in this world, sorry. It seems reasonable to me that the ouside rail should be slightly higher than the inside one to distribute the loads better, although it would be speed dependent.

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10 hours ago, RobinofLoxley said:

Actually I meant camber, not banking. Im not a professionnal in this world, sorry. It seems reasonable to me that the ouside rail should be slightly higher than the inside one to distribute the loads better, although it would be speed dependent.

 

In model trains cant / superelevation serves no operational purpose and is only a visual effect - the result of the fact that physics doesn't scale and we use wheels that are way out of profile compared to the real thing.

Edited by mdvle
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Back in the early 1980s I built a German branch line layout in HO, about 3.5m x 0.5m wide, a plan taken from a German track plans book. It originally went to a couple of reversing loops rather than the usual fiddle yard and it worked well. A move of house meant that I could then expand it, so built a helix at on end to a set of loops underneath plus a reverse loop so there was no need to handle any of the stock except if it derailed!

 

The helix was built into  plywood box for transport and was from memory 4 circles of 8mm ply supported by 6mm threaded rod for easy adjustment. I used Lima 1st radius curves for the inner track as I had a load in stock and 2nd radius for the outer track. The inner track was used to send trains down for obvious reasons. I never really had a problem with locos pulling or pushing trains up, though they were limited 6 coaches by layout length. Some of the very long German coaches such as the Silberlings (silverfish) scale length didn't like the tight corners but didn't give any problems.

 

The layout attended a few shows but was dismantled pre a further house move. 

 

The helix was a major talking point as it seemed to be unique on the British exhibition circuit. That layout gave me many years of pleasure. Quite how British stock coped with the helix I can't remember.

 

The other thing was the helix was operated automatically using good old-fashioned relays and could stack 4 trains on the upward spiral, along with 6 in the loops and 3 on the reverse loop gave quite a variety of stock.

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An interesting feature of gradients, and thus helices, is reported here:

 

Knowledgeable members suggest this is related to modern worm drives, not DCC. Something else to factor in to a helix design...

 

Edited by Harlequin
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On 03/08/2020 at 09:34, RobinofLoxley said:

Finally and more generally, no-one has mentioned banking. Is it just not done?

 

On 04/08/2020 at 13:11, RobinofLoxley said:

Actually I meant camber, not banking. Im not a professionnal in this world, sorry. It seems reasonable to me that the ouside rail should be slightly higher than the inside one to distribute the loads better, although it would be speed dependent.


I’ve seen a recommendation that any track in a helix which trains would be climbing should have negative camber i.e. the outside rail should be lower than the inside one. This is to counteract the traction forces which pull towards the inside  of the curve, and tend to cause derailing to the inside - ‘stringlining’. 

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3 hours ago, pH said:

I’ve seen a recommendation that any track in a helix which trains would be climbing should have negative camber i.e. the outside rail should be lower than the inside one. This is to counteract the traction forces which pull towards the inside  of the curve, and tend to cause derailing to the inside - ‘stringlining’. 

 

Interesting thought, wonder if it would really work.

 

I think more generally the advice would be to keep things as simple as possible - a helix is already complicated enough to build with problematic access to fix things in the future.

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4 hours ago, pH said:

 


I’ve seen a recommendation that any track in a helix which trains would be climbing should have negative camber i.e. the outside rail should be lower than the inside one. This is to counteract the traction forces which pull towards the inside  of the curve, and tend to cause derailing to the inside - ‘stringlining’. 

 

Although not on a helix, one of the reversing loops on my father's layout does indeed have adverse camber on it as a Hornby Javelin used to derail on it otherwise.

 

Back on Helixes, for some years I helped operate Julain Evison's layout 'Khan', which was effectively an African rabbit warren where trains either gradually worked their way up a mountain side and helixed back down inside the mountain or vice versa (there were various passing places en route so trains could travel in alternate directions). 

 

Trains were usually an 0-6-0 and three or four bogie coaches or wagons (although on one occasion Ted Polet put a much larger Namibian loco on the layout which negotiated it all without problems until it caught the final spiral support on the way back down).

 

Generally speaking it worked pretty well, but on the occasions a train got stuck/derailed partway through the helix it could be quite difficult to get at, involving grovelling on one's knees and standing up inside it. It also wasn't unknown for a wagon to come uncoupled near the top and roll back down....

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16 hours ago, RJS1977 said:

 

Although not on a helix, one of the reversing loops on my father's layout does indeed have adverse camber on it as a Hornby Javelin used to derail on it otherwise.

 

Back on Helixes, for some years I helped operate Julain Evison's layout 'Khan', which was effectively an African rabbit warren where trains either gradually worked their way up a mountain side and helixed back down inside the mountain or vice versa (there were various passing places en route so trains could travel in alternate directions). 

 

Trains were usually an 0-6-0 and three or four bogie coaches or wagons (although on one occasion Ted Polet put a much larger Namibian loco on the layout which negotiated it all without problems until it caught the final spiral support on the way back down).

 

Generally speaking it worked pretty well, but on the occasions a train got stuck/derailed partway through the helix it could be quite difficult to get at, involving grovelling on one's knees and standing up inside it. It also wasn't unknown for a wagon to come uncoupled near the top and roll back down....

 

Here it is..

 

B776EBE5-3C58-4449-AE96-913D2DEC6C3D.jpeg.6063d20f0b345280a0147cbdfe61099a.jpeg

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  • 2 weeks later...

I'm going to give Helixes a thumbs up :-)

 

My layout is about 23' x 10' in the shape of a big "U" with double track forming a continuous run around the inside and the outside of the "U", that makes for about 100' long run on each track. On one side of the "U" there is a junction with double track heading off towards the middle of the baseboard then curving round and heading up to pass over the main lines as they double back, then it joins the helix and spirals down to the storage layer below.

 

It is 4 ft diameter with the up line on the outside of the helix, down line on the inside. Loco and train wise, Hornby 56s, Bachmann 47s and pairs of 20s have no problem storming up, or even creeping up, with rakes of 24 HAAs with some temporary weights in the wagons. Hornby 50s, Bachy 47s & 37s handle 10 coach trains no problem

Heljan 47s barely notice whatever load you put on them. Bachmann 25s.... slip some on the heaviest loads. Heljan 33s can do 7 coach mk2 rakes no problem, still an open verdict on longer/heavier freights. 

 

Even some of my Lima 47s can do it - the re-motored ones with extra weights are just fine. Upgraded ones with the original motor but more weights and pickups do ok too. Of the original 47s, it is a bit hit and miss.

 

For practical hauling concerns, the helix works well. It has blended into the overall operation of the layout (pics are from a while back, all track laying is finished and trains are running around it all now) and it works. I can bring a train up, run it around a few times then into a loop or siding while i bring another up... next train i can turn around by a diagonal link line across the middle of the main board then route it back down the helix to storage again, while bringing another up to hold at signals on the main layout until i do something with the one before it.

 

Couplings are a killer issue though, and to a lesser extent weighting of wagons. I am finding where there is real mismatch in height f couplings within a train then it is a recipe for derailment, usually at the bottom of the helix. Overly light wagons contribute to this by deleting even easier. I haven't tried it with 3 link couplings yet.... but i do plan to soon :-)

 

Yeah, overall i would recommend a helix. Be prepared to do a fair bit of fiddling and adjusting, but worth the effort.

 

Here's a few pics of mine from when it was under construction.

 

 

Helix-1.jpg.af2c9ac7bd2d8b46dd752ab035e7c13a.jpg

 

Construction was nowhere near as bad as I expected. A friend with skills in woodworking helped me with this, each circle is in three parts and is cut by hand from stencils marked on plywood sheets - the sides are not perfectly circular, but good enough. These are screwed at each end onto wooden cross pieces that are supported on the metal screw rods, their heights being adjustable as they sit on washers & screws.

 

Hardest part was the track laying - initially i was going to go with flexitrack but after getting one circle done i gave up on that and ordered 5 complete circles of Hornby 3rd and 4th radius double curves, that reduced the flexitrack to just some short sections at the top and the bottom. The total height gain is ~18 inches - just enough space i figured i would need if i ever had to crawl underneath with a soldering iron to fix something !!

 

Helix-3.jpg.9fe6bbe6315b5d9deb65ce96590d478e.jpg

 

Down below there is an 11 track storage yard that has sidings  that vary in length, the longest holding 10-11 coach trains plus loco or 24 HAA hoppers plus a pair of 20s. From the storage yard there is a return line that loops round 180' and returns to the  

 

This was the slowest part of the layout as i spent about a year testing the reliability of the yard and helix - testing, testing, fixing things, testing, tweaking things and then some more testing - that is the single biggest point i would recommend to anyone planning a 2 level layout, test the snot out of the lower levels before you put the top boards in place.

 

Here's the lower yard & helix while i was waiting for the Hornby 3rd & 4th curves to arrive

 

Helix-4.jpg.e4113eec77e5cece68213e074aaddbe8.jpg

 

Lower yard has enough clearance for me to stick my head and shoulders under. Lighting is from one of those el-cheapo 5m long strips of LED lights you can get on ebay. I had originally planned on installing two but one turned out to cast all the light needed down below 

 

Helix-2.jpg.91f40afe2a2338a18267d70929318e34.jpg

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Looks great 47406 - note that you used ply, it is very smart.

 

We got trains running again on the layout yesterday and did some testing with the Class 41 - this is an ancient Hornby HST with the pewter cab conversion, and remotored with Hornby Class 67 motor and bogies, using a Bachmann Junior DCC chip. Was very impressed it managed well with 9 old coaches in tow, struggled with 10. Makes me confident that 2 power cars will do ok with a full HST rake.

 

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2 hours ago, 47406 said:

 

Couplings are a killer issue though, and to a lesser extent weighting of wagons. I am finding where there is real mismatch in height f couplings within a train then it is a recipe for derailment, usually at the bottom of the helix. Overly light wagons contribute to this by deleting even easier. I haven't tried it with 3 link couplings yet.... but i do plan to soon :-)

 

Tension lock couplers are a PITA, but 3 link are worse (except on P4) as there is too much clearance between flanges and rail head so wagons get askew and buffers then disengage and lock on downhills. US style centre couplers, Kadee etc couplers or H/D  Peco type solve the problem to a large extent.  Adjusting tension locks to a common height is great if you have two or three spare lifetimes.   With DCC if you want to use 3 links ( or tension locks) then have a working brake van to keep couplings taut. I really don't know why Hormbach or some such haven't produced one RTR, its not rocket science to have a working brake you can apply or release at will.

Once again it seems 2ft radius Helices work well with Diesels.  Be interesting to see how a big steamer gets on, P2, GWR 47XX  or Crab may struggle with their long coupled wheelbases

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19 hours ago, DavidCBroad said:

Tension lock couplers are a PITA, but 3 link are worse (except on P4) as there is too much clearance between flanges and rail head so wagons get askew and buffers then disengage and lock on downhills. US style centre couplers, Kadee etc couplers or H/D  Peco type solve the problem to a large extent.  Adjusting tension locks to a common height is great if you have two or three spare lifetimes.  

 

oh lordy, isn't that the truth !

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On 31/08/2020 at 05:03, 47406 said:

Hardest part was the track laying - initially i was going to go with flexitrack but after getting one circle done i gave up on that and ordered 5 complete circles of Hornby 3rd and 4th radius double curves, that reduced the flexitrack to just some short sections at the top and the bottom.

 

For those where the needed radius doesn't neatly align with existing curved track another option is to buy/create some sort of jig/form to create the curve you need.

 

An option if you are in North America (or perhaps the UK depending on what the shipping costs are / if one (eventually) travels to North America) is a product called SweepSticks from Fast Tracks - laser cut "guides" that go between the rails on flex track to either keep it perfectly straight or to give a radius you want - and designed to also allow perfect spacing of side by side tracks

 

https://www.handlaidtrack.com/sweepsticks-ho

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  • 1 month later...

Back in May 2020 I started building my first big multi level layout in the top room which is around 16' x 8'.

Twice around the room in OO Gauge with a Fiddle yard on one side on the lower level and a higher level station.

Fiddle yard was ok and the double junction on the opposite side was good

1736419589_IMG1108.JPG.5f3574d7420a6225aaa28e206a0fa74d.JPG

 

410677193_IMG1140.JPG.61e941a8203affd9959c91821274571a.JPG

 

But when I tried to make the gradient work to the upper level I came stuck as it was too steep.

 

The track plan was revised to start from the Fiddle yard then via a Helix to the upper level station then across the far end of the room on the level and along the back wall in to a second Helix to bring the track down to the lower level going back the opposite way and in to the Fiddle yard - As both Helix are double track based on 2nd/3rd radius set track I will still have two circuits doing the run around the room.

 

The Helix is a Kit from ebay https://www.ebay.co.uk/itm/Model-Railway-Helix-Kit-00-scale/282382269004

The first part of the Helix is here and it will be 1.5 turns to reach the High level

IMG-1337.JPG.ccb72f86c351c25f850e21128b6b785f.JPG

 

It is keeping me occupied :)

 

Peter

 

 

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  • 2 weeks later...
On 25/10/2020 at 19:45, Peter749 said:

The Helix is a Kit from ebay https://www.ebay.co.uk/itm/Model-Railway-Helix-Kit-00-scale/282382269004

The first part of the Helix is here and it will be 1.5 turns to reach the High level

IMG-1337.JPG.ccb72f86c351c25f850e21128b6b785f.JPG

 

It is keeping me occupied :)

 

Peter

 

 

 

Unfortunately the sections are not cut accurately with a lot of messing to try and make it work 

Three week later and still having problems with it

 

Should have bought a professional version but not many in the UK

 

Peter

 

 

 

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4 hours ago, Peter749 said:

 

Unfortunately the sections are not cut accurately with a lot of messing to try and make it work 

Three week later and still having problems with it

 

Should have bought a professional version but not many in the UK

 

Peter

 

 

 

 

Try White Rose, their Helix is well made and works.

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On 29/10/2020 at 21:52, JST said:

I am watching with interest the videos of the helix Charlie Bishop is building at Chadwick model railways. Worth a look.

Same here, be interesting to see, fair chance it will work but then he’ll have another track layout rethink anyway lol.

In 4mm helixes seem a lot of work to get reliable, and due to the necessary size, they must be reliable because access will be so difficult for derailments or even cleaning. 

 

On my N gauge layout, I don’t have a helix exactly, but split level return loops minimum 11 inch radius and they are easy to access and haven’t caused any issues. I laid them with streamline to save money which was fiddly to get right, if money was no object I’d be using set track and a quality kit.
 

Edited by Largechris
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