Main line terminus in OO

[jamespetts]

Thank you for your replies.  I attach for reference an output from SCARM showing just the helix, but both upper and lower levels at once, as it might have been difficult to see the transition between them with the two levels separated.

 

As can be seen, the helix only needs to pass under the first track at 7,100mm from the far left wall (or 400mm from the far right wall), not at the point where I have placed the tunnel start markers. At that point, the level separation is specified as 70mm and the gradient on the pre-helix section is < 2% (as measured by SCARM).

 

As to the height separation between turns on the helix, I have taken this from this commercial product, a 3rd/4th radius helix kit for OO gauge, which gives a separation per turn of 76mm. Somewhere between 5-6 turns would be necessary to achieve the 45cm drop in this case (and if something less than an integral number of turns is necessary, one can always continue the same curve on the flat at the bottom, of course).

 

As to steam locomotives using a 3rd/4th radius helix,

is a video of a Hornby B1 hauling an 8 carriage train up just such a helix (look at the end of the video for the haulage section), albeit on the outer (4th radius) curve. This person is using the DCC Concepts Power Base (as revealed in another of his videos).

 

is an American video (of fairly poor quality) showing an HO scale steam locomotive pulling a very long train up a helix of 18" (457.2mm) at some speed.

 

Mightbe - the reason that I do not always unquestioningly defer to all suggestions made here is that they sometimes contradict other information, such as in the videos above. I am afraid that I do not think that there is any reason to criticise empiricism - it is really the only reliable way of dealing with conflicting information.

 

In relation to whether the helix needs to be double track - it would be a lot more convenient for it to be double track, as a single track helix might well create bottlenecks. However, if a single track helix would be the only way of making this work, it might be worth considering. Given the conflicting information and incomplete data about the extent to which a double track helix (with 3rd radius on the ascent) is likely to be workable, I shall probably have to test this (with and without the Power Base) to see whether this is the case before finalising the layout design.

 

I shall be very interested in the results of Denbridge's PowerBase tests in due course.

 

Incidentally, in relation to the level separation: I wonder whether 400mm would be sufficient? That would allow me to have the N gauge layout at 1600mm, which is acceptable for viewing given that I am quite tall, and reaching to the back of that could be facilitated with a simple kick stool. The lower level would then be at 800mm and the upper level of this layout at 120mm. This would also reduce the number of turns required in the helix.

 

Incidentally, well spotted on the single/double slip error: I have now corrected this.

Edited March 1, 2018 by jamespetts

[Dagworth]

is an American video (of fairly poor quality) showing an HO scale steam locomotive pulling a very long train up a helix of 18" (457.2mm) at some speed.

 

That's N gauge

 

Andi

[Denbridge]

That's N gauge

 

Andi

And 18" equates to 36" in OO

[sigtech]

I believe that this forum is missing a "we told you so" button....

Edited March 1, 2018 by sigtech

[Denbridge]

Thank you for your replies.  I attach for reference an output from SCARM showing just the helix, but both upper and lower levels at once, as it might have been difficult to see the transition between them with the two levels separated.

 

As can be seen, the helix only needs to pass under the first track at 7,100mm from the far left wall (or 400mm from the far right wall), not at the point where I have placed the tunnel start markers. At that point, the level separation is specified as 70mm and the gradient on the pre-helix section is < 2% (as measured by SCARM).

 

As to the height separation between turns on the helix, I have taken this from this commercial product, a 3rd/4th radius helix kit for OO gauge, which gives a separation per turn of 76mm. Somewhere between 5-6 turns would be necessary to achieve the 45cm drop in this case (and if something less than an integral number of turns is necessary, one can always continue the same curve on the flat at the bottom, of course).

 

As to steam locomotives using a 3rd/4th radius helix,

is a video of a Hornby B1 hauling an 8 carriage train up just such a helix (look at the end of the video for the haulage section), albeit on the outer (4th radius) curve. This person is using the DCC Concepts Power Base (as revealed in another of his videos).

 

is an American video (of fairly poor quality) showing an HO scale steam locomotive pulling a very long train up a helix of 18" (457.2mm) at some speed.

 

Mightbe - the reason that I do not always unquestioningly defer to all suggestions made here is that they sometimes contradict other information, such as in the videos above. I am afraid that I do not think that there is any reason to criticise empiricism - it is really the only reliable way of dealing with conflicting information.

 

In relation to whether the helix needs to be double track - it would be a lot more convenient for it to be double track, as a single track helix might well create bottlenecks. However, if a single track helix would be the only way of making this work, it might be worth considering. Given the conflicting information and incomplete data about the extent to which a double track helix (with 3rd radius on the ascent) is likely to be workable, I shall probably have to test this (with and without the Power Base) to see whether this is the case before finalising the layout design.

 

I shall be very interested in the results of Denbridge's PowerBase tests in due course.

 

Incidentally, in relation to the level separation: I wonder whether 400mm would be sufficient? That would allow me to have the N gauge layout at 1600mm, which is acceptable for viewing given that I am quite tall, and reaching to the back of that could be facilitated with a simple kick stool. The lower level would then be at 800mm and the upper level of this layout at 120mm. This would also reduce the number of turns required in the helix.

 

Incidentally, well spotted on the single/double slip error: I have now corrected this.

Hi. 400 mm is nowhere near enough clearance to get in to do maintenance. Especially since you would have to get to tracks at the back of the lower board. add to the fact you will have a scenic area at the front. Even an open area inside the lower board would be of no help. the average person only has a reach of say 70cm and since 400mm will only allow you to slide your arm in, that is as far as you'll get :/

[Fenman]

I believe that this forum is missing a "we told you so" button....

 

Yes, but...

 

Former London mayor Ken Livingstone predicted some cock-up would result from a new policy of his successor, Boris.

 

It duly came to pass. Ken was interviewed and asked if he'd like to point out that he had warned of exactly that. Ken replied - surprisingly modestly, in the circumstances - that he declined to do so, because "in the whole of human history, no human has *ever* looked more sexually attractive as a result of saying 'I told you so'...".

 

Paul

[James Makin]

I’ve read through the whole thread and I do sympathise with the OP, James, I well remember wanting my first layout to be based upon the largest plan in my ‘Bible’ at the time, the legendary 1990s Hornby trackplans catalogue, a 12x4ft beauty, but alas I never had the space or the budget as a youngster! In hindsight now, I recognise that this was too big and not realistic enough, but it was a tough one to swallow at the time!

 

Can I possibly offer some completely contrary advice? You seem to have a very clear, determined plan on what you want, so I would suggest that if you do have the time, the space and the money, then just crack on with it and see how you go!

 

You’ll doubtless make mistakes along the way (we all do) - just get the boards built in your shed and then start playing around with the track formations until you’re happy, and it all works! Then you can see if the Helixes are feasible or play around with the platforms acccordingly.

 

If I can offer any advice for a 21st Century modeller, (and I’m so very sorry admins!!) - don’t waste hours on the likes of RMWeb and social media, just spend that time doing modelling! I find it far too easy to waste valuable free time these days when you can be doing something productive instead of being online, just get out in that new shed, get something running, tinker around and have some fun!!

 

Cheers,

James

[Harlequin]

Thank you for your replies.  I attach for reference an output from SCARM showing just the helix, but both upper and lower levels at once, as it might have been difficult to see the transition between them with the two levels separated.

 

As can be seen, the helix only needs to pass under the first track at 7,100mm from the far left wall (or 400mm from the far right wall), not at the point where I have placed the tunnel start markers. At that point, the level separation is specified as 70mm and the gradient on the pre-helix section is < 2% (as measured by SCARM).

 

Your numbers broadly agree with mine, then.

 

Does SCARM's 70mm separation between levels take account of the thickness of the board?

 

I suspect not and if we assume 9mm ply is used then the gap for the track work and train on the helix to pass under the topmost platform line is actually 70-9 = 61mm. That is perilously close to my measured loco+track height of 60mm, any small variation in vehicle height for whatever reason will cause a collision and note that my calculated height does NOT include underlay or powerbase plates...

 

I'm 99% certain that traffic on the helix will collide with the baseboard supporting the topmost platform line, as things are currently designed (and that's assuming that you can give the baseboard enough support around the helix while avoiding the support frame from interfering with the track).

 

I think you will have to increase the gradient leading to the helix at the very least.

 

But that would be just another bodge on top of a series of previous bodges and bad choices that have led to this frankly ridiculous situation. And I can't believe that you're even taking Joseph's suggestion of an additional height-adjustable N gauge layout seriously. Are you sure he wasn't joking?

Edited March 1, 2018 by Harlequin

[Harlequin]

I’ve read through the whole thread and I do sympathise with the OP, James, I well remember wanting my first layout to be based upon the largest plan in my ‘Bible’ at the time, the legendary 1990s Hornby trackplans catalogue, a 12x4ft beauty, but alas I never had the space or the budget as a youngster! In hindsight now, I recognise that this was too big and not realistic enough, but it was a tough one to swallow at the time!

 

Can I possibly offer some completely contrary advice? You seem to have a very clear, determined plan on what you want, so I would suggest that if you do have the time, the space and the money, then just crack on with it and see how you go!

 

You’ll doubtless make mistakes along the way (we all do) - just get the boards built in your shed and then start playing around with the track formations until you’re happy, and it all works! Then you can see if the Helixes are feasible or play around with the platforms acccordingly.

 

If I can offer any advice for a 21st Century modeller, (and I’m so very sorry admins!!) - don’t waste hours on the likes of RMWeb and social media, just spend that time doing modelling! I find it far too easy to waste valuable free time these days when you can be doing something productive instead of being online, just get out in that new shed, get something running, tinker around and have some fun!!

 

Cheers,

James

 

Well that just about puts the lid on this thread, then, doesn't it! We've clearly been wasting our time giving you (James Petts) feedback and now you're being told you've been wasting your time listening to it. 

 

I'm out.

Edited March 1, 2018 by Harlequin

[James Makin]

Well that just about puts the lid on this thread, then, doesn't it! We've clearly been wasting our time giving you feedback and now you're being told you've been wasting your time listening to it. 

 

I'm out.

I’m a different James, Phil

 

I’ve already built a few odd layouts hehe

 

Cheers,

James

[Denbridge]

Well that just about puts the lid on this thread, then, doesn't it! We've clearly been wasting our time giving you feedback and now you're being told you've been wasting your time listening to it. 

 

I'm out.

Part of me wishes rmweb had been around in my younger inexperienced days. I might have avoided some costly and frustrating mistakes. One thing I'll never change though is good old fashioned hands on planning. One thing I've seen so much of, is how easy it is to plan totally impractical layouts on a computer

[Joseph_Pestell]

 

But that would be just another bodge on top of a series of previous bodges and bad choices that have led to this frankly ridiculous situation. And I can't believe that you're even taking Joseph's suggestion of an additional height-adjustable N gauge layout seriously. Are you sure he wasn't joking?

 

Why would I be joking? And nothing wrong theoretically with your idea of counterbalancing it with a layout along the opposite wall. Many a true word spoken in jest.

 

It was James' idea to have an N gauge layout in the shed as well as the 00. I am just looking at a way of making that possible.

 

I don't suppose either that I have really invented anything new here. There must be a lot of space-starved modellers who could use a layout that lifts up out of the way. After all, few of us are more than 6'6" tall and live in houses with 8' ceilings. That's a lot of wasted volume that could store a layout.

[Philou]

If I can just add my tuppence worth (or 2 centimes if you will ), when I were a lad and we had no internet, we had CJ Freezer's plans handbooks, pencil, piece of paper, a huge rubber and drew lots of plans and did track laying - and inevitably something would have gone wrong and it was a case of start again. I will say that today, seemingly we may spend sometime behind these 'ere screens - at least by the dissemination of information rapidly between lots of people, we can get advice and be aware of potential pitfalls that may await us sooner than rather when it is too late, and that is a positive thing. Of course, sometimes advice is not taken up for ....... well, reasons. Whilst I agree that there's nothing better than 'doing things', some of us are cautious and others (like me) may not have anywhere to enable a start just yet.

 

For space saving, again when I were a lad, in our house where the ceilings were high, I made a layout in my bedroom measuring approximately 8'6" x 10'6" that folded up completely against one wall floor to ceiling - and it was only about 9" deep - so it took little space.

 

Cheers,

 

Philip

[Denbridge]

If I can just add my tuppence worth (or 2 centimes if you will ), when I were a lad and we had no internet, we had CJ Freezer's plans handbooks, pencil, piece of paper, a huge rubber and drew lots of plans and did track laying - and inevitably something would have gone wrong and it was a case of start again. I will say that today, seemingly we may spend sometime behind these 'ere screens - at least by the dissemination of information rapidly between lots of people, we can get advice and be aware of potential pitfalls that may await us sooner than rather when it is too late, and that is a positive thing. Of course, sometimes advice is not taken up for ....... well, reasons. Whilst I agree that there's nothing better than 'doing things', some of us are cautious and others (like me) may not have anywhere to enable a start just yet.

 

For space saving, again when I were a lad, in our house where the ceilings were high, I made a layout in my bedroom measuring approximately 8'6" x 10'6" that folded up completely against one wall floor to ceiling - and it was only about 9" deep - so it took little space.

 

Cheers,

 

Philip

I think one of the points that has come across on here (not just this thread) is that it seems common for designs to be mapped out on a computer that would just never work in reality for one reason or another. I think most people gained their ideas from dear old CJF or from magazine articles, so at least were basing their ideas on established, working formulae. I remember well the instances where a 'Freezer' plan was expanded and the builder complained his trains wouldn't run properly. CJF designed most of his plans around a minimum 18" radius and trains of 4-5 coaches maximum. They worked well, within those constraints

[Denbridge]

Your numbers broadly agree with mine, then.

 

Does SCARM's 70mm separation between levels take account of the thickness of the board?

 

I suspect not and if we assume 9mm ply is used then the gap for the track work and train on the helix to pass under the topmost platform line is actually 70-9 = 61mm. That is perilously close to my measured loco+track height of 60mm, any small variation in vehicle height for whatever reason will cause a collision and note that my calculated height does NOT include underlay or powerbase plates...

 

I'm 99% certain that traffic on the helix will collide with the baseboard supporting the topmost platform line, as things are currently designed (and that's assuming that you can give the baseboard enough support around the helix with that support frame also interfering with the trackways.

 

I think you will have to increase the gradient leading to the helix at the very least.

 

But that would be just another bodge on top of a series of previous bodges and bad choices that have led to this frankly ridiculous situation. And I can't believe that you're even taking Joseph's suggestion of an additional height-adjustable N gauge layout seriously. Are you sure he wasn't joking?

No amount of tweaking and changes will alter the fact that it is completely impractical. Even getting trains to go up the helix is a waste of time if you can't get to the tracks to undertake repairs, undertake essential 'deep' cleaning, or rescue/re-rail a rogue train vehicle. As Scottie often remarked "Yea canna change the laws of physics Jim

[rob D2]

You'd need the patience of a Buddhist monk to realise the plan, with the financial power of Elon musk, if you possess these qualities go right ahead.

[jamespetts]

Thank you for all those who have contributed further feedback: it is much appreciated. My apologies for having mis-identified the N gauge helix as HO gauge; I thought that I had searched specifically for OO/HO gauge helices and the gauge was not apparent from the title. However, the fact t hat this particular helix is N gauge does not, of course, tell us anything about whether a 3rd/4th radius helix would be workable in OO gauge. The other link is definitely of an OO gauge railway layout and definitely of a 3rd/4th radius helix and a steam locomotive hauling an 8 carriage train up it, albeit with the assistance of PowerBase. I should note that, if it comes to pass that the trains cannot climb the incline, even with magnetic assistance, on the 3rd radius inner curve, the track could always be singled and the 4th radius outer curve used, albeit at a loss of some capacity.

 

As to the descent to the helix, the 70mm is railhead to railhead height. This could easily be increased to 76mm (the separation height of the commercial helix) whilst allowing the gradient on the flat to remain at a reasonable percentage. I do not understand why there should be any problem in particular with doing this. Thank you for pointing out the error in the original calculations, however.

 

In relation to helix maintenance, the problems described would, of course, be common to all helices. Given that these are a common feature of model railways/railroads and have apparently been common in the US for decades, it is simply not plausible that these are insurmountable obstacles that make such an arrangement "completely impractical".

 

I went along to the Model Railway Club in London this evening, incidentally, and picked up an application form. The people there were most helpful. There was a chap there who knows well the fellow who runs the McKinley Railway, who was confident that a 3rd/4th radius helix (which he advised be laid with Setrack on account of the tendency of flexible track to kink on tight turns, albeit not the steel sort owing to its propensity to rust) would be workable, and who also usefully advised connecting point motors to plugs so that they can easily be replaced in the event of a failure. He suggested building a test track of about 1-2m in length with one or two points to familiarise myself with the skills of track laying and basic wiring (and to have a useful test track separate from the main model), and thought that a 400mm level separation (provided that the wiring be done sensibly, e.g., with plugs for point motors) between layers should be sufficient, which may well make it possible for me to build the N gauge layout after all.

 

Incidentally, I should be very interested to meet a Bhuddist monk with the financial power of Elon Musk, although I doubt that such a person would spend much time building model railways.

Edited March 2, 2018 by jamespetts

[mightbe]

Have you ever seen a helix in the context of a North American layout? Because of your approach here, trying to tuck it under a station with minimal clearance, I think not. Here's a description:

 

Helices are fairly common in North America; let even more layout fit into a huge space. They can often be found in corners, near utility areas, or in the middle of a peninsula. The average size of a layout with a helix is typically 250 sq feet at least (usually in the environs of 400 sq ft), and actually become more common the larger the layout is. (That is the scale of things here.) Helices are usually designed such that the gradient does not exceed 2% (1 in 50 as would be said in the UK), requiring a fairly large radius of about 30". More severe gradients can be found on such layouts (almost never more than 3%), usually on sections of dead-straight track.

 

Helices are almost never obstructed from above, at least not by anything that isn't removable (such as a hillside), and often they are designed so that a person can stand inside them for maintenance and cleaning. If a "standing" arrangement is impractical, a helix is usually unobstructed from most or all sides, again with generous access from above.

 

I urge you to compare the above with what you have. 

 

You helix is:

1) tightly radiused (if your layout is designed 'by numbers' 1st, 2nd, 3rd, etc, your curves are too tight--doubly so for a helix)

2) steep as all get-out

3) covered by an immobile and immense mini-Paddington

4) obstructed from 2 sides, arguably 3.

5) designed into a layout that is probably not large enough to justify it

 

Quentin

Edited March 2, 2018 by mightbe

[Pete the Elaner]

 

I went along to the Model Railway Club in London this evening, incidentally, and picked up an application form. The people there were most helpful. There was a chap there who knows well the fellow who runs the McKinley Railway, who was confident that a 3rd/4th radius helix (which he advised be laid with Setrack on account of the tendency of flexible track to kink on tight turns, albeit not the steel sort owing to its propensity to rust) would be workable, and who also usefully advised connecting point motors to plugs so that they can easily be replaced in the event of a failure. He suggested building a test track of about 1-2m in length with one or two points to familiarise myself with the skills of track laying and basic wiring (and to have a useful test track separate from the main model),

In what way is a test track any different to a smaller layout, which is a suggestion you have already dismissed many times?

Most early layouts don't go far beyond track on boards anyway. We realise we could have done some things better & decide that the best way is to start again from scratch.

[Denbridge]

You still havent given any consideration as to how you will gain access to those yards and yards of track on the lower level, forgetting the helix for now. Even a800mm space between would be insufficient to gain access to over 50% of that trackage.

[jamespetts]

Thank you for your thoughts. As noted earlier, the plan is to allow access to inside the helix from below by having a hole in the centre, as well, of course, as from the side. I accept that access from the top would be more convenient, but it is hard to see how access from below and the side between them would be impossible or unworkable.

 

As to the radius, I do not think that anything short of data is really going to help me in this regard, given the conflicting information that I have had so far on the point: simply re-stating that it will not work without data really does not assist at all.

 

In relation to lower track access, may I ask: what do you believe is the correct means of calculating the necessary height for access to any given width? Given that I have had conflicting information on this, it is necessary to be rigorously empirical in approach.

 

In relation to the test track - this is different to a smaller layout in that it does not need to have enough time, effort and space invested in it to be operationally satisfying to me: it merely has to serve the utility of allowing me to test things and need not have, for example, scenery or point motors.

[Fenman]

...

In relation to lower track access, may I ask: what do you believe is the correct means of calculating the necessary height for access to any given width? Given that I have had conflicting information on this, it is necessary to be rigorously empirical in approach.

...

 

I would have thought this would be an easy one to test empirically - you could mock it up with a few cornflake packets and try reaching into the gap, then adjusting until it was satisfactory?

 

Paul

[jamespetts]

I would have thought this would be an easy one to test empirically - you could mock it up with a few cornflake packets and try reaching into the gap, then adjusting until it was satisfactory?

 

Paul

 

I am not sure that I have that many cornflake packets.

[gordon s]

It's not only a matter of re railing stock or seeing whats there, lets assume you have a turnout fail.  You're going to have to get your head and shoulders in there to see what the problem is.  Then you have to add the focal length of your eyesight to focus on the track and deal with the problem.

 

I have boards of a similar depth with track at the back edges and if I can get out into the garage later will fetch in a sheet of ply and then prop it up to try to see.  Of course it won't mean a lot as at 70 the focal length of my eyes is much longer that someone of 37.  With glasses on I can down to 6".  I'm guessing it's going to be 450-500mm.

 

At the outset of ET, I had the exactly the same issues.  I listened to what people had to say, but in some cases couldn't see the problems and thought they were being negative.  It wasn't until I started to build in three dimensions did I appreciate the issues.  Hidden track is one thing, hidden track with pointwork is a no.  There are a multitude of things under a baseboard.  Not only the framing, but point motors and wiring from the upper level.  You will often find point motors from the upper level are right over the lower level track meaning you have to redesign on or both to avoid clashes or have to allow additional clearance.

 

I appreciate you are having your boards made, but how you connect between them all is often skipped over as it's something you think you can visualise.  It's not until the have the boards in front of you can you appreciate the difficulties.

 

Think about how you are going to lay the track.  In situ or in sections, one at a time?  Both have advantages and disadvantages.  Both have an impact in the layout construction when it comes to the precise alignment needed in both planes to ensure trouble free running. 

[Denbridge]

As i mentioned previously,the average person only has a reach of about 30 inches. Your base boards are deeper than that. It isnt just about reaching either. To do some jobs youll need to use both hands. Plus you need to see what you are doing. So, youll need to get your whole upper body in the space under the terminus and be able to work in that space.