Spirals to change levels...

[Matt]

Hi All,

 

Have finally gotten my first baseboards into the railway room and am now approaching the next stage with trepidation. My layout will have two levels approx 18" apart with the lower level serving as a fiddle yard to the scenic upper level. My plan is to link the two with a spiral of approx 5' x 6' which I reckon will give me a gradient of better than 1 in 60 if I raise each spiral at approx 2.5" each turn. I have some ideas how to tackle this but am interested to hear from anyone else who has tried this and any pointers would be welcome... The spiral needs to be 4 track and was intending on using 3rd radius curves for the innermost line.

 

Cheers,

Matt

[Kenton]

IMO FWIW a gradient of 1:60 on a helix is too steep.... and even too steep for a straight gradient.

They are difficult enough to build in the first place - it would be awful to build one and then find you cannot run anything up it - just for the sake of a couple more turns.

[RFS]

1-in-60 should not be a problem at all, especially with diesels that have traction tyres. I have upper and lower sections on my layout where the ruling gradient is 1-in-60, and steam locos will take 8 coaches up it with no problem, even though most of the climb is on 3ft radius curves. I had to remove the weights from the Bachmann MK1 coaches, otherwise the limit was 6. Even my lovely Hornby T9 will take 4 Maunsell coaches up this!

 

It's really down to what length of trains you need to run and what the motive power is.

[gordon s]

Matt, if you have a spiral of 6' diameter that will give you a length of 226" for each circle. With a 2.5" rise, that would be a gradient of 1:90 which is better than you first thought. To climb 18" will require just seven layers, which is around 132' in length.

 

Reducing the diameter to 5', reduces the length per cicle to 189" which increases the gradient to 1:76 and reduces the overall length to 110'.

 

Will you be running steam or diesels? What length of trains will you expect to run?

 

On straight track, those would be no problem, but on a continual curved incline of between 110' and 132' in length, the drag weight of the train will certainly have the effect of increasing the gradient. With heavy loads, there is a possibility of string lining with coaches/wagons being pulled off the track as the train tries to straighten itself and take the shortest route.

 

It's an interesting concept, so let us know how you get on. I'm sure it can be done, but my preference would be the 6' diameter as a minimum, larger still if you have the space as it's the diameter of the spiral that changes the gradient, not the number of turns.

[Mike-Greg]

Matt, if you have a spiral of 6' diameter that will give you a length of 226" for each circle. With a 2.5" rise, that would be a gradient of 1:90 which is better than you first thought. To climb 18" will require just seven layers, which is around 132' in length.

 

Reducing the diameter to 5', reduces the length per cicle to 189" which increases the gradient to 1:76 and reduces the overall length to 110'.

 

Will you be running steam or diesels? What length of trains will you expect to run?

 

On straight track, those would be no problem, but on a continual curved incline of between 110' and 132' in length, the drag weight of the train will certainly have the effect of increasing the gradient. With heavy loads, there is a possibility of string lining with coaches/wagons being pulled off the track as the train tries to straighten itself and take the shortest route.

 

It's an interesting concept, so let us know how you get on. I'm sure it can be done, but my preference would be the 6' daimeter as a minimum, larger still if you have the space as it's the diameter of the spiral that changes the gradient, not the number of turns.

 

I have just build a helix for my layout

it occupies 1 mtr x 1 mtr

goes up 2.5 turns

not sure exact the hight change but it is around 30cm

all my stock goes up ok

both steam tanks ( Fairburn ) and the class 20-25

aditingly they only pull 2 coaches or 6 or 7 4 wheel wagons

 

if you look at the photo it runs fron the lwer level to the top of the main section

[tebee]

Four tracks with only 2.5 inch separating turns is going to result in the inner tracks being inaccessible for maintenance, cleaning and sorting out derailments. Is that 2.5 inches is the distance from the top of one level to the bottom of the next or the separation from one rail level to the next? if it's the latter the thickness of the baseboard and the track itself would probably result in too tight clearances anyway.

 

As regards construction, I've used 1/4 inch threaded rod going from top to bottom, one inside and one outside at about 1ft spacing and a nut and washer above and below the track base for each level. The track was laid directly on 1/2 inch ply - I used shuttering ply but doing it again I would use a better quality. The whole thing was mounted on a base of 7/8 ply. It took a LOT of setting up !

 

A simpler method is to use wood blocks between each level but they need to be accurately sized and the first level set up very carefully.

 

Tom

[Mike-Greg]

I used thredded rod as well 8 lenghts with nuts top and bottom

these went through the 18mm base ply at the bottom you can see in the pic

its only single track and the hole in the bottom is so i can get in if any derailment

with the track layed i can just get a hand in over a loco or coach to lift it out

each ring had lugs sticking out both on the outside and inside

these rings were all layed flat ontop of the bace and i driled through them all

at the same time to get the alignment correct, and through the base at the same time

the rods go throught the base with nuts top and bottom

the rings were cut out of 8mm ply

the finished helix is very ridgid

and the track was layed direct to the ply with PVA wood glue

I cant give you a pic of the helix as i am away at work (at sea) no pics of it on the laptop

but it works very well

[Matt]

Thanks for all the replies. I realise I should probably have provided a little more detail so here goes...

 

I model Blue diesels through to current day - mostly Bachmann with a few Heljan / Hornby / ViTrains thrown in. Most of these don't have traction tyres. I do have some superdetailed Lima but won't be expecting much haulage from these!

 

Most of the trains will be around 6-8 coaches in length with a couple of HSTs (new Hornby) and a sleeper a bit longer. Freightwise most won't be too long although I do plan to run a 30 wagon MGR coal train and a 20 wagon TEA oil wagon train (behind pair Bach 37s or Hornby 60 or Bach 66).

 

The base board for my spiral is 5' x 6' but needs to accomodate 4 tracks - the inside track will obviously be tightest and I was working on basis of 4' diameter giving approx 14' circumference (1' straight on 6' section) which works out as 168" circumference to gain approx 2.5" height (which will be more like 3" when i factor in the forgotten thickness of the ply) which gets me somewhere near 1 in 60 i think. The outer tracks will be better than this.

 

I actually need two of these - one for each end of the layout... - at one end the outer tracks will carry the long trains but at the other I can't see a way of engineering it such that the outer tracks carry the longer trains

 

I like the idea of threaded rod and clamping the whole lot together to drill holes and get in the right place. My father in law also suggested at the weekend that the best way of making the sections all the same would be to set up a template to use as a fence for the jigsaw (alas no band saws here).

 

Overall though I am starting to feel this might be a tall order and am thinking whether there is a better way to ascend the gradient (like a straight gradient along the back of the fiddle yard although to climb 18" at 1 in 60 would require 90' (if my maths is correct) which I wish I had... alternative is to raise fiddle yard but then would not have much clearance to changeover stock etc especially given scenic down sections + use of tortoise motors on upper level...

 

Will keep posted on where I go with this - might subcontract the work to my local joiner!

 

M

 

 

[tebee]

Well having had a helix on my last layout, I've avoided putting one on the new one ! I like having multiple decks, in my case both where scenic( or would have been had I have got that far !) I like running trains from A to B and it's hard with even quite a large space to get a decent run on one level with out having train pass through the same scene multiple times.

 

For my style of operation - I follow my train round from one station to the next - I found two annoyances with using the helix. Firstly the amount of time the train disappears while traversing it, running slow freights at a scale 25-30 MPH it was something like three minutes. Secondly I always found it difficult to get a grip of the concept that if you where looking at a train travelling right to left on the lower deck it was going Eastbound, but after it had gone up the helix to the upper deck that same train was going left to right but was still Eastbound.

 

I realize with your operating concept, especially if you operate in a more typical "British" style these may not affect you but they irritated the hell out of me!

 

So the new layout is a "nolix" triple deck ( in places) but gradually gaining hight as it winds its way around the walls and along both sides of a central peninsular. Its in a 18 X 10 ft room which is about the minimum you can get away with for this configuration . Even then I've had to drop my minimum radius from 34 in on the old layout to 24in. Worst gradient is 1 in 50 but it's a fairly minor line so I'm running shortish trains. I get about a 240 ft single track run from fiddle yard to the far terminus with 6 intermediate stations. After a year in planning and 18 months construction it's about one third complete but external forces have prevented me doing much recently. I'm planning to get started again soon !

 

Tom

[Doorslammer]

I'm having a think about this type of layout design, although on the lesser scale of two tracks on one side of the board and one for the other side. The long Class 158s would be the outermost extremity in length, but having a Bachmann Class 37 pulling 5 (maybe 6 or 7 in the future) Lima Mk2s uphill, amongst other things.

 

I don't think there is much experience of spirals out here, but I'll be interested to find out what people can theorise on Saturday at the club.

 

PS As such, I haven't got basic board measurements as yet or relative heights as such, but thinking about it I probably wouldn't need to set the lower level any lower than two trains high.

[tebee]

Helix's may not be popular in Aus or the UK yet - I only know of one other UK layout that used one and, like mine it was US prototype, but there are a lot in the US. There is a multi deck layout group on Yahoo now. I've had a look around and found a few links showing different approaches to making them .

 

 

http://anemrr.ejpj.com/Seq02.htm

 

http://www.onewolf.org/trains.htm

 

http://users.rcn.com/weyand/tractronics/helix/hlxartcl.htm

 

http://www.railroad-line.com/discussion/topic.asp?TOPIC_ID=26555

 

And some videos

 

 

 

 

And a helix in a kit

 

http://www.easyhelix.com/design.htm

[Donw]

If your trains are travelling at a scale 60mph thats around 1ft per minute on the layout so if you have 120ft of track on the helix thats 2 mins just going up or down. I suspect the will spend more time on the helix than running on the rest of the layout.

Just a thought

Donw

[Bloodnok]

I'm planning a helix on my garage layout - to gain height from the under-board fiddleyard to the scenic area (which will be uninterrupted across the entire top surface of the layout). One way down will have enough linear distance to drop at a sensible gradient, but the other needs the helix to gain height within the space available. I expect to leave nearly the entire first turn 'visible' in the scenic area (with the track in a cutting) to assist with derailment cleanups, which will leave me with about 270 degrees of turn hidden from view. Even so, I still expect that part is going to be a pain in the proverbial to get access to when derailments occur - I'm not currently sure whether to leave the underneath very open and go in via that route, or whether to make lumps of scenery removable to allow access from above (or even both!)

[dave1905]

In the US they are called a "helix". There are several ways to build them.

 

The roadbed itself is usually plywood, 1/4 to 1/2 inch is typical in the US. I have seen and worked on two methods. One is to cut curved "arcs" of plywood and then join them with splices.

I also tried cutting arcs of 1/4" plywood and then overlapping the sections and glueing them together to make a roughly 1/2 in spiral with no visible splices in it. I wasn't happy with that method because my ability to smoothly laminate the pieces wasn't that good. Possibly a better carpenter would have better results.

 

Another method is to cut straight sections to form a hexagonal or octagonal spiral. This method supposedly uses less wood. I have asembled one helix using this method and I dislike the number of splices it requires, plus I think it doesn't appreciably save you that much wood, since the other spiral we built at the same time used the arc construction.

 

Once you have the roadbed there are many ways to build it, 3 common ones are:

1. Threaded rods. Cut the roadbed wide enough to put a rod on both sides of the roadbed and still clear the trains. Assemble the helix and drill holes a bit larger than the rod at six places around the helix (more if the diameter is larger, you wnat a rod every 16-24 inches minimum). Thread the rods up through the holes, adding a washer and nut above and below each level. Use a short 12-24" level and a spacer block to set the grade consistent. Adjust the nuts to raise, lower and level the helix.

2. Spacer blocks. Cut blocks of wood to the distance you want between the top of the roadbed and the bottom of the layer above it. Place the blocks between the layers of roadbed every 16-24" around the edges.

3. Edge spacers. at at least 6 places around the perimeter place a vertial piece of wood as a riser and screw a small block of wood to the riser with a single screw, spaced at the spacing of the levels of the helix. Rest each level on the top of the block of wood and then screw or nail it to the riser. By using a single screw in the block, it will rotate to match the incline of the roadbed.

 

The threaded rod method takes a lot of tweaking to get it smooth (use a spacer block as a gauge to set the spacing between layers) but allows the most flexibility to tweak.

 

Dave H.

[Etched Pixels]

Depending on the location there is another way to build a helix layout which is to build the entire baseboards as a spiral round the room. One loop of the room takes you from the bottom fiddle around the room (more than once in some extreme cases!) to an upper yard. That way for a split level layout you only need to climb from the lower to upper level in one loop of the room.

 

For short stuff offscene (and especially handy for microlayouts) never overlook the heath robinson solutions like sections of train elevator.

 

Alan

[tebee]

Depending on the location there is another way to build a helix layout which is to build the entire baseboards as a spiral round the room.

 

 

Hers some pics of my half completed line which uses this form of construction, - it also has a branch off the top level which will rises in the opposite direction eventually becoming another separate level at my eye hight 68 in - I may need to use a step to operate this !

 

 

The Metal uprights down the centre of the room will eventually support a double sided peninsular. The middle level ( on a yellow foam board, I used savaged materials which has conveniently let me colour code the levels !) as it comes into this peninsular on the left is on a somewhat lower level than when it leaves it on the right. The high level branch terminus is above on the right on the blue boards. If you follow there along the back wall you can see the middle level gently rising while the branch falls. the blue board to the left will eventually lead to the main line terminus on the peninsular. The green board at the bottom will eventually be extended along the back wall where all the blue stock boxes are now. It will rise up slowly like the middle level. The fiddle yard is off to the left on this level.

 

 

 

We are now looking to the right of previous photo - the two levels merge together roughly in the far corner of the room after this they are one level with two levels of track. The next section of the layout is using some boards salvaged from my last layout and construction changes from foam board to plywood in the foreground.

 

 

And here is the junction where the branch finally joins the main line. The blue board in the distance is the top level leading to the upper terminus that was on the left in the first photo. Underneath you can see the middle level tracks and at the bottom the fiddle yard.

[Gwiwer]

Always worth remembering when you consider a spiral that curvature increases drag significantly and that in turn has a big impact on the length of trains which can be run. Many of us might have relatively sharp curves which take the track around, give or take, a 90 degree corner to the room or board. Most trains would be longer than the curve itself or only be traversing it for a few moments. The effect of drag is fairly small.

 

When you introduce a spiral you are creating several continuous 360 degree curves and your train will be entirely on the curve for some time. A train which copes perfectly with a 90 degree layout corner may not do so with a spiral. Or you might find you need to keep increasing the power as it climbs to maintain forward motion.

 

Then you have to factor in slope angle. Try for yourself laying out a complete circle of track and dragging a few coaches around by hand. Feel the resistance and the weight? Now place some risers under that track such that it starts to resemble a spiral and repeat the drag. Quite a difference, yes? And we are asking our 12V motors to cope with this sort of thing using nothing but gravity for adhesion. Some will and some just will not. Some will gamely struggle with a decent train and others will make it every time. And the one train you really want to show off (because we all have one, don't we?) is the one that just refuses to work at all.

 

I know of a couple of UK-based, UK-themed layout using spirals and of a few elsewhere in the world. All seem to have some issues with curve radius and gradient. And most seem to have miscalculated the vertical separation required between loops to successfully keep the tracks clean or retrieve derailments.

 

Spirals do have a place in our model world. But be very wary of asking too much in too small a space.

[Matt]

Again - thanks to all those that have replied to this theme. Following feedback I have decided to steer clear of the spirals I was planning. Instead, have opted for a more conventional setup with the fiddle yard on the opposite side from the scenic with a central control well. This has taken up a bit more space but planning permission has been applied for and granted and the boards were reconfigured at the weekend to suit the new set-up. Am still working the detail on the FY but reckon I should be able to squeeze 30 or so tracks in by splitting levels and avoiding gradients in excess of 1 in 60 (on straights!).

 

Thanks again for the advice - will post pics one day when things make some progress (may be a while given time demands of a 1 yr old and the strange decision I have made to hand build all the track...).

 

M

[roythebus]

I built a German HO layout in the 1990s with a spiral using 2 and 3 radius! there was a bit of a problem with a fleischmann 262 tank derailing sometimes, but even scale length long DB coaches ran up and down it with no problems, even in push pull mode. I also had an auto block on the upward spiral so I could stack 3 trains on it.

 

The layout, Rath Ost, was seen at several shows, including IMREX, Epsom, Oxford GRS, Model Engineer. The spiral was built using 6mm ply cut with a jigsaw, using 1/4" threaded rods to maintain the gradient. the layout became life expired so is no more. Or should that be life-expiralled?