helix Does a helix ever really work?

[chuffinghell]

My helix works perfectly

 

 

[Trog]

Bachmann G2a or 3F tank would take about 25/30 wagons, the Garratt would pull a train about 20' long. But sadly derailed its front bogie every time on an awkward reverse where the track came off the spiral and through the wall into my workshop. 

[Trog]

1 minute ago, chuffinghell said:

My helix works perfectly

 

 

 

as a rule?

[scottystitch]

I built a helix for a previous layout, in N gauge.  It was a 1% constant gradient. and was designed to ensure that Farish & Dapol steam locomotives, both tender and locomotive drive, could haul prototypical 12 coach trains up and down. It achieved those aims, in fact it was very successful.  Diesel locomotives were less of a problem; I think a Farish 47 took 19 Mk1s up and down.

 

I don't have the dimensions to hand, but it it was roughly 18-20" radius with around 48" straights along one axis (it was essentially a rectangle with rounded corners) and lifted 2" per revolution.

 

The helix was there to enable the storage yard to be immediately under the layout due to lack of space in the garage.  It no longer exists due to a house move and a change of circumstances.

 

I do agree with the view about devices to "enhance" adhesion, having tried DCC Concepts magnetic system and seeing no difference between with and without.

 

Best

 

Scott.

 

 

Edited June 6, 2020 by scottystitch

[spamcan61]

1 hour ago, Trog said:

I had an oval helix of 3rd and 4th radius with a couple of feet of straight track between each 180' curve on my layout with a gradient of 1 in 37. The outer track was ascending and I used steel rail track. It caused no problems and I was able to run reasonable length trains on it. The limiting factor was a nickel steel crossover on one of the straights, well loaded ascending locos would sometimes slip to a stand on this having successfully rounded the curved section on the steel rails.

IMHO it's a pity that nickel silver track has become pretty much universal, given that steel gives better adhesion in most cases.

[Corbs]

I forgot to add that the main reason we did include a helix was at it allowed us to double the size of the scenic area of the layout. We can have the whole top deck scenic as well as roughly a third of the bottom deck, with the fiddle yards and return loops taking up the rest. We can also have 2 stations rather than one.

[DCB]

5 hours ago, Trog said:

I had an oval helix of 3rd and 4th radius with a couple of feet of straight track between each 180' curve on my layout with a gradient of 1 in 37. The outer track was ascending and I used steel rail track. It caused no problems and I was able to run reasonable length trains on it. The limiting factor was a nickel steel crossover on one of the straights, well loaded ascending locos would sometimes slip to a stand on this having successfully rounded the curved section on the steel rails.

 

Did you run any very long 4 wheel stock like the Lima CCT? as per my pic.   Did you have the same problem I have with inside wheels lifting?

Good point about Steel track and adhesion, I find dirty steel track grips better than clean steel, after a few runs a  train which initially sails up then slips to a halt until it is lightened by at least one coach.  Obviously old magnadhesion  locos approx halve their haulage on N/S points within an otherwise steel layout.

 

5 hours ago, Trog said:

Bachmann G2a or 3F tank would take about 25/30 wagons, the Garratt would pull a train about 20' long. But sadly derailed its front bogie every time on an awkward reverse where the track came off the spiral and through the wall into my workshop. 

 

Was it lack of play on the bogie/ pony truck?  I find a lot of RTR needs the pivots altered to allow a lot more up and down and twist to stay on the rails on some of my more dramatic changes of elevation.  I use Peco couplings and often float the coupling bar on the bogie or pony so the coupling can force the wheels down but not lift them when pulling or pushing / banking

[mdvle]

17 hours ago, Harlequin said:

Whenever I see a helix being proposed in a layout design my immediate reaction is, "Oh dear. Never mind. Maybe your next layout will work..."

 

I wonder if we could establish the minimum parameters of a working helix for two distinct scenarios:

• Helix Scenario A: Steam traction with 6 or 8 driven (coupled) wheels, hauling 8 bogie coaches or 24 non-bogie wagons.
• Helix Scenario B: "Modern image" traction with 4 or 8 driven wheels spread across one or two locos or power cars, hauling 8 bogie coaches or 24 non-bogie wagons.

Edit: I am thinking mainly about helices within the typically restricted spaces of British layouts and as a contained sub-part of the layout rather than being wound around and through the layout.

 

My first thought is what exactly do you have in mind that you think a helix is the solution for?

 

You try putting a constraint on the design - typical restricted space of a British layout - but at the same time are putting minimum parameters that exceed most British layouts in the need to run with 8 coach trains.

 

So which is it?  Is it a typical small space layout, or is it a layout that can accommodate full length trains?  Because the available size dictates where in the benefit/drawback ratio a helix fits.

 

I also suspect that you are going to have to be more specific than "steam traction with 6 or 8 driven wheels" given the variability of performance between different models - and as the maximum grade topic on here indicates at the end of the day it will likely be a case of testing whatever it is that you hope to use to see if that specific model can do what you want.

[Trog]

6 hours ago, DavidCBroad said:

 

Did you run any very long 4 wheel stock like the Lima CCT? as per my pic.   Did you have the same problem I have with inside wheels lifting?

Good point about Steel track and adhesion, I find dirty steel track grips better than clean steel, after a few runs a  train which initially sails up then slips to a halt until it is lightened by at least one coach.  Obviously old magnadhesion  locos approx halve their haulage on N/S points within an otherwise steel layout.

 

 

Was it lack of play on the bogie/ pony truck?  I find a lot of RTR needs the pivots altered to allow a lot more up and down and twist to stay on the rails on some of my more dramatic changes of elevation.  I use Peco couplings and often float the coupling bar on the bogie or pony so the coupling can force the wheels down but not lift them when pulling or pushing / banking

 

I don't have that much in the way of long wheelbase four wheel stock beyond some Ratio four wheel coaches and Tube wagons, but I had no problems with stock derailing on the helix.

 

As for the Garratt I tried loosening the truck, I tried tightening it, I checked the gauge of the wheels and fitted new ones nothing worked. Then one of the motors jammed, and that stopped it derailing, in fact it stopped it full stop.

[Enterprisingwestern]

13 hours ago, chuffinghell said:

My helix works perfectly

 

 

 

You're so transparent!

 

Mike.

[scottystitch]

27 minutes ago, Enterprisingwestern said:

 

You're so transparent!

 

Mike.

In fairness, it was a very measured reply

[scottystitch]

12 hours ago, scottystitch said:

I built a helix for a previous layout, in N gauge.  It was a 1% constant gradient. and was designed to ensure that Farish & Dapol steam locomotives, both tender and locomotive drive, could haul prototypical 12 coach trains up and down. It achieved those aims, in fact it was very successful.  Diesel locomotives were less of a problem; I think a Farish 47 took 19 Mk1s up and down.

 

 

 

 

I've just realised, that wording is very Trump-esque..

 

"It was a great helix. Very great. The greatest helix ever made. Probably. It was so great. So great. And Farish and Dapol paid for it. Not one penny of my money was spent on it"

scott

[kingmender]

Do they work? Yes.

I belong to Waverley Model Railway Club in Melbourne and we have two permanent club layouts each with a helix to transition between layout decks approx 24" appart. One being HO/OO which I run on the other being N Gauge. As a British steam modeller I run mainly GWR and LMS. Kings and Castles easily pull 8 Hawksworth coaches or 10 Airfix Centenary coaches up the Helix which is approx 36" radius and 1:70 gradient. 42xx/72xx and 28xx haul 50 wagon trains with ease too and my Hattons/Heljan Garret slipped to a stand with 100 open wagons but managed 90!

My home layout has a smaller double track helix of 30" and 32" radius with the up line on the outer achieving 1:64 gradient. Haulage capacity is similar although varies from loco to loco even of the same design. A friends Castle (current tooling) struggles with 5 where all 3 of mine (same tooling - Beaverston, Swindona and Wellington) all haul 6 or more.

Why do I have a helix? My layout is (or more correctly will be) a railway system. Much like others shown in this thread. It enables trains to be run between stations with realistic time between each. The first level has a through station based on Trowbridge and a shed. Second level is based on Moreton in Marsh with a branch to a Cleevdon based terminus. top level (via second helix) will have a Badminton based station and storage loops for the rest of the world.

A few construction pictures of the first helix attached.

Similarly a friends layout has 3 levels and multiple stations based on a section of one of the (closed) lines between Melbourne and Sydney. Prototypically it is single track with passing at stations except we have no change of gauge at the border (Vic 5'3", NSW 4'81/2"). Operating nights with 8 or ten of us get really interesting particularly if large amounts of Aussie red wine are consumed.

Edited June 11, 2020 by kingmender

[Harlequin]

Hi @kingmender,

That's really interesting.

What are the approximate overall sizes of the layouts you mention that use helices?

 

[Corbs]

All these pics and the description are in our layout thread but I thought it worth reposting.

The method we ended up with was borne of being fed up with us changing our minds and just deciding to attack it.

 

We used MDF (sealed with dilute PVA) - bought some 8x4 sheets which the mill cut into 4x4. This was determined by 2nd, 3rd and 4th radius curves. We couldn't be bothered to faff around with flexi as it's easier for Hornby/Peco to design the curves for us!

 

Drilled a hole in the centre and used a tin of tuna (John West) to draw round for the nubbins.

The string was used to draw one circle 4 ft diameter.

 

 

Cut the master out with the jigsaw.

 

Clamp the master to the other sheets and trace them (because I can't be bothered to mark out and measure properly more than once)

 

Cut them all out and you have rings

 

 

The rings were all marked in the same place and we used a circular saw to slice them so we can bend them vertically.

 

We used threaded bar with washers and nuts wound on them to space the helix. I would never permanently fix the helix in place because I often make mistakes so it's easier to correct things if it's not screwed in to wood.

The threaded bar method allows us to dial in the gradient - we ended up reducing the clearance above the stock and adding another layer because too many locos struggled.

 

 

This view shows the sandwich plates that hold the rings together.

 

When you drill the holes for the threaded bar, clamp them all together and drill through all the layers to ensure alignment, then number the nubbins so the orientation is always the same.

 

 

 

One (very important) note - HELIXES ARE HEAVY!

 

We underestimated the weight and had to go back and add much more reinforcement to the support structure underneath to avoid it sagging.

Edited June 11, 2020 by Corbs

[Enterprisingwestern]

 

That's going to be a bloody big Audi!

 

Mike.

[Harlequin]

2 minutes ago, Enterprisingwestern said:

 

That's going to be a bloody big Audi!

 

Mike.

Slight miscalculation of scale.

 

[Corbs]

4ft to the millimetre isn't it?

 

[rockershovel]

The once-popular “rabbit Warren” 009 layouts included one or more partial helix ; a few minutes surfing around turns up at least three exhibition layouts including some version of the Ddualt spiral. 

 

Heres a version of the “round the room to the next level” type http://www.009dutch.nl/cdr/main/eframe.htm

Edited June 12, 2020 by rockershovel

[kingmender]

18 hours ago, Harlequin said:

Hi @kingmender,

That's really interesting.

What are the approximate overall sizes of the layouts you mention that use helices?

 

My railway room is approx 30' x12' narrowing to 10' at one end. The two helicies are in the corners on the long straight wall. I've added some images of the track plans from XtrackCAD. Door to the room is on this side too at the end of teh shed. I've used a "swing bridge" section to fold the track out of the way. The top level will cut across the doorway at about 1800 from the floor but will only be about 300 wide.

My friends shed is L shaped being approx 16' x 24' with a 12' x 8' leg. The club layout is in a room of approx 60' x 40' whch houses the N gauge in the middle and the Ho/OO around the outside. Our website is offline currently but can normally be found here and has images of the 2 permanent layouts. www.waverleymrc.org.au 

[RobinofLoxley]

The use of threaded bar to control the helix structure is an inspiration.

 

But one question bugs me. Given the large change of level from top to bottom of a helix, what does this do for oversight of the layout? You have some at high level and some at a much lower level, however you cut it, or have you fitted hydraulic lifts into your stools?

 

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

[Corbs]

Admittedly a long video but here's one of the little locos banking a heavy goods up the helix, I can't wait to get it done and operating properly!

 

 

[mdvle]

2 hours ago, RobinofLoxley said:

But one question bugs me. Given the large change of level from top to bottom of a helix, what does this do for oversight of the layout? You have some at high level and some at a much lower level, however you cut it, or have you fitted hydraulic lifts into your stools?

 

Most layouts large enough to need a Helix and a second deck are operated while standing, as stools are no longer normally practical given the need to follow the train.

 

Or, to put it another way, you don't normally build a helix for a 1'x4' plank.

 

2 hours ago, RobinofLoxley said:

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

 

Depends on the layout.

 

But given the helix is generally more of an American thing, and most models of American trains are way overpowered with multiple locos, there generally isn't a need for a banker/helper.

 

That said, I have heard of some layouts using it though (at least for banking from the rear) you need to be careful you don't push the train off the curve.

[Harlequin]

54 minutes ago, Corbs said:

Admittedly a long video but here's one of the little locos banking a heavy goods up the helix, I can't wait to get it done and operating properly!

 

Lovely video!

 

(I thought we were going to watch the train lumber past without missing a beat and then see the same loco at the back...! )

 

Is the rear loco coupled up or just buffered?

 

[Corbs]

Just now, Harlequin said:

Is the rear loco coupled up or just buffered?

 

 

Thanks  it's coupled in the video, the train has a mix of TLs and Kadees but I think will eventually be just Kadees. I had wondered about taking the spring out of the knuckle on the banking locos' front coupling so it's just acting as a buffing plate? Then we might be able to do the graceful dropping away at the summit. Hopefully one of these days I'll do my model of 92079 specifically for this task...