Main line terminus in OO

[jamespetts]

Thank you for all of your replies. I am aware of the King's Cross layout, as I saw the Youtube videos over a year ago now. It is indeed impressive. I counted 113 turnouts (including diamonds and slips) on that layout, although I may be off by one or two.

 

If one is using this to calibrate the rate of progress that I am likely to make on this layout, that does not seem to be plausible, as that would suggest a rate of one turnout every 3 months on average for the last 30 years (installation and wiring; I use turnout count rather than linear meters as I do not have the measurement of the trackage on that layout in linear meters). I note that it is an analogue which would make the wiring on a larger scale layout more complex than it would be in DCC (not that DCC wiring is not capable of being complex). This seems to be entirely out of line with the other data point so far available, and we do not know how intensively that this was worked on over that time: there might have been gaps decades long with no work at all.

 

In relation to curve radii, the data by those who have very helpfully tested on this thread suggests that this is not an insurmountable obstacle, although it does pose challenges and may require extra adhesion on some locomotives.

 

In relation to baseboards, as I have stated previously, I intend to have these made professionally, as I do not have any skill for woodwork, so the difficulties of the baseboard construction would not of themselves be something with which I need directly concern myself. I do not think it practical to attempt to make this layout modular or portable.

 

In relation to a pulley system for the possible N gauge layout, this seems to be fraught with difficulty. If it were achievable within reasonable parameters, that would be potentially attractive, but I do not know whether the roof could support the weight, whether it would be too awkward to use, whether a sufficiently reliable system could be devised, or whether the equipment would need more clearance than is reasonably available.

[mightbe]

If you've never built a layout, why are you trying to figure out how long it takes to do xyz? 

 

You might stop work on one thing and move to another, or spend months working out how to achieve abc. It's not a linear process, and definitely not something you can calculate. I can build a P4 turnout in 2 leisurely days, yet at the moment I only have one finished turnout on my test track and part of a slip. Why did I stop? Haven't had the time. You can't plan on future enthusiasm or time commitments. 

 

Quentin

[jamespetts]

The reason that I am trying to calculate how long that building the layout will take is because it has been suggested that building the layout will take a long time and that I should take that into consideration when choosing what sort of layout to build. I need to be able to quantify that to some extent to be able to make any meaningful decisions based on it.

 

In any event, I have now further revised the layout design. For some reason, I cannot attach files, so I have had to upload them to a server. Here is the revised upper level:

 

 

and here is the revised lower level:

 

 

As you will note, I have moved the engine shed to the far corner of the layout. I was concerned about reach/access distances, but, by altering the station throat layout and moving the lower level station back, I have been able to achieve the recommended 900mm front to back reach distance in the engine shed area. This has allowed for a slightly larger engine shed and one with more direct access to the station throat without conflicting with the carriage sidings.

 

I have also shortened the platforms a little: the longest pair of platforms can still take 12 carriage trains (indeed, it could take a 13 carriage train, but that would not fit in the carriage sidings), and the next longest two pairs of platforms can take 11 carriage trains. The carriage sidings has one road that can take 12 carriages, and the others (bar the short one) can take 11 carriages.

 

Moving the depot has enabled me to straighten the fiddle yard sidings as recommended, which are shown on the plan. I have also altered the layout of the fiddle yard so that the main line trains run around the outer reversing loop whereas the relief line trains run around the inner reversing loop. I have extended the length of the fiddle yards slightly so that the ends of them will oversail the workbench a little more, but at ~1.2m in height, this should not be too much of a problem. I have also slackened the curves at the left hand side of the layout plan.

 

The result of all that is that trains on the main lines (as opposed to the relief lines) and in the carriage sidings never have to negotiate a curve of less than 572mm radius (4th radius in Hornby/Setrack terms), and never have to negotiate, even in the fiddle yards, short radius points. Trains on the relief lines in the fiddle yards must be able to negotiate 3rd radius curves and short radius points, but an express train dispatched from the station onto the relief lines for any reason can cross onto the main lines before circumnavigating the reversing loop. Short and medium radius points are, as before, confined to the fiddle yard/non-scenic areas. Only trains using the lower level will have to negotiate 438mm (2nd radius equivalent) curves and only trains passing between the upper and lower levels (via the helix) need to traverse any sort of gradient. Trains using the lower levels will either be electric stock or tank engine hauled suburban stock with trains no longer than 6 carriages, which (perhaps with a bit of magnetic assistance on the helix) should be able to manage the tight curves from what I have been able to discover so far.

 

Hopefully, with the long trains (whether in the sidings or on the main line) no longer having to traverse any curve of <572mm, it should not be necessary to use magnetic assistance other than on the helix, and only a limited range of stock will need to use this.

 

This revised plan is still usable with GWR stock owing to the ability to use 12 carriage trains. It remains a "track heavy" layout, but that is really a matter of taste rather than practicality. Moving the depot does not allow the town scene that I had imagined, but has helped to solve a lot of practical issues with the previous version, so it is probably worthwhile.

 

If I take a fancy to Midland/LMS/ex-Midland stock in the future, I could always just switch out the stock on this layout and have a whole new operating experience. (Indeed, one might even do the same with the LNER/GNR, as that, too, had a connexion to the City Widened Lines).

 

In any event, I should be grateful for any feedback on the revised plan. Your feedback so far has been most invaluable.

[Dagworth]

Small helices, DO NOT DO IT
Learn the lessons others have tried before.
"Newcomers to model railroading often hope a helix somehow magically negates the laws of physics. Sadly, such is not the case. Besides the steepness of the grade itself in such a tight helix, the extra friction of the cars on the tight curve radii adds to the effective grade, making it nearly impossible to pull any length of cars without stringlining (pulling and derailing to the inside of the curve).
See this thread for similar discussion. In it, I mention the example of Joe Fugate, who found his 24" radius helix was not sufficiently broad and did major layout surgery to tear it out and replace it with a much larger radius.
http://cs.trains.com/forums/1473626/ShowPost.aspx
Byron"

http://cs.trains.com/mrr/f/11/t/135176.aspx

 

And that 24" radius is a full 25% larger than you are proposing, third radius Hornby curves are less than 18" radius. 

 
Andi

Edited February 28, 2018 by Dagworth

[Harlequin]

The new larger images are great and I applaud the intention behind a lot of the changes but the big concepts still seem to be all wrong to me, I'm afraid.

 

Purely technically, there's a huge problem with the position of the helix: Assuming that the lines from the top level start to descend at the tunnel symbols and that the helix uses the minimum gradient, it will take almost a full turn before there's enough clearance above it for any other lines to pass above.

 

[Edit:] Even if the lines to the helix start descending as soon as they turn away from the platforms in the middle of the design there's probably not enough clearance at the ends of the platforms because of the likely substantial baseboard support depth at that point. (And the transition from a gradient to the helix could be tricky.)

 

In other words, as drawn the helix lines conflict with the ends of all the platform lines.

 

The obvious place for the helix is inside the reversing loops.

Edited February 28, 2018 by Harlequin

[mightbe]

I'm not sure you need to quantify it; I won't pin a number to it. It's going to take a long time, full stop. And that's if it is completed. One can hope but there's no guarantee.

 

(The majority of layouts go unfinished, and a much higher percentage of ambitious one-man projects. Gordon S--whose woodworking, engineering, track laying, and design skills are evident to all who visit his thread--has had to restart Eastwood town many times, and it's a much more straightforward layout than what you propose. Will it be finished? I hope so and wish Gordon the very best! He has the skills and accumulated experience to do it. You, with respect, do not. Even accounting for the differing approaches, I suspect this layout will take at least twice as long as any prediction could guess [without major revisions, rebuilding, or anything like that].)

 

The fiddle yard is looking better aside from the inexplicable diamonds and the way they 'feed' into the scenic layout. I think you can get away with a single mass of storage tracks there and far less bizarrerie in getting trains to and from the correct tracks.

 

To remind you, there seems to be a profound lack of flow to the left end of the platforms. I feel you could cut a pair of platforms and wind up with a better and more realistic station.

 

As a side note, in the quest for an optimal layout you've made your station less realistic--it wasn't common for every platform to be 100% interchangeable until much later in the 20th century. Slow and Fast could have their own platforms, and there were usually a few platforms that could only do arrivals or departures, just not both.

 

Quentin

 

EDIT: To Harlequin, I suspect the gradient begins ASAP after the junction. I don't know if that's enough space to dip 3.5" but it's possible.

Edited February 28, 2018 by mightbe

[Harlequin]

EDIT: To Harlequin, I suspect the gradient begins ASAP after the junction. I don't know if that's enough space to dip 3.5" but it's possible.

Hi Quentin, We cross-posted.

 

Yes, I twigged that after I posted but I'm dubious there's enough room to drop below the baseboard support structure: Say 3000mm @ 1:36 = 83mm drop - probably not enough.

 

So is the solution an even steeper gradient before the helix with powerbase under both the helix and the gradient? Things are getting even more complicated...

[gordon s]

With regard to Kings Cross, I don't think anyone is suggesting it took 30 years to build at a constant rate.  During that time there would have been numerous sections working and I'm sure plans will have changed to accommodate unforeseen issues.  No matter how well you plan in two dimensional drawings, it's not until you actually start to build your layout do you find that problems arise that never occurred to you in the planning stage.

 

I suspect the comment started 30 years ago is the same as my own experience.  I started ET over 10 years ago, but the latest incarnation has only been under construction for a year or so.  Even over that period there have been numerous unforeseen situations, none of which are layout related that have stopped the build.  The list is endless.  Family demands, other interests, upkeep of my home and sadly, bereavement, all brought ET production to a halt.

 

The estimates that have been calculated all assume that nothing else is going to happen in your life and that you can perform every day with the same level of enthusiasm and efficiency.  That isn't going to happen.  Building a layout is not a competition or a race and personal experience has shown that setting yourself timescales brings in a deadline and additional pressure.  One of the reasons I reduced the number of updates on ET, was to be able to stroll through the build and not worry that little had been done in days or even weeks.

 

This is a great hobby and should be enjoyed.  Don't worry about the time at all.  It will take as long as it takes and you may find the journey there is the really enjoyable bit.  Many find that once a layout is 'completed' they get bored and start on their next project.

[Silver Sidelines]

Looks great but sadly won't work..  I have a lot of videos on YouTube showing weighted Bachmann and Hornby locomotives at the limits of their haulage capacity on 36 inch radius curves and nominal 1 in 60 gradients.  All on analogue, I think that digital control in this instance would be very problematic.

 

For example Duke of Gloucetser here:

 

 

You may also find this video made with the Branor Systems Cam Truck instructive.  The model scenery is rubbish but there are some good views of the structure used to support the curves and gradients.

 

 

I undertook the construction myself.  I am not sure how you would subcontract the woodwork when plans need to be somewhat flexible.

 

Cheers

 

Ray

[Joseph_Pestell]

 

 

In relation to a pulley system for the possible N gauge layout, this seems to be fraught with difficulty. If it were achievable within reasonable parameters, that would be potentially attractive, but I do not know whether the roof could support the weight, whether it would be too awkward to use, whether a sufficiently reliable system could be devised, or whether the equipment would need more clearance than is reasonably available.

 

Weight of an N gauge layout, 24' x 2'8", would not be inconsiderable but, with the right baseboard construction, is well within the capacity of structural loading that is implied by a shed of that size.

 

Given the size, I would not be looking to support all the weight from the roof but mounting the frame of the layout on sliding runners (as on kitchen units) fixed vertically to the wall, probably at 60cm intervals but might need to be 40cm. Apart from spreading the weight better, it enables the cables that raise/drop the layout to be behind the layout, against the wall. It would probably be best to have an electric winch but they are not too expensive.

Edited February 28, 2018 by Joseph_Pestell

[Junctionmad]

My summary

 

I can’t see the helix working in the space provided and the lift height necessary

 

3h a day every day is a totally unrealistic expectation. Remember “ logic is a method of going wrong with confidence”

 

Again seek to extract a subset that can be got running in 6 months.

 

Servo installs , took about 1 hour per point, this was with already fabricated mounts and turnout operating units. initial servo installs were much slower

 

If yiur having externally made baseboards , there no reason not to make then portable , just put them on trestles as opposed to fixing to the wall. Working under a baseboard is a huge PIA.

 

The layout ( from memory ) had about 25 points , most of which were in the fiddle yard , which was comparatively fast to lay

 

Time estimate I provided was from bare baseboard and included laying underlay

 

I would agree with others that your layout is a 5-10 year undertaking to get to the point of full automated running , is your mojo up to that ?

 

Surely a smaller 00 , to prove concepts and demonstrate your build speed and level of continuous commitment is a useful alternative , aim for something you feel you could complete inside 12 months.

Losing 1 year out of 10 isn’t much.

[Denbridge]

Thank you for all of your replies. I am aware of the King's Cross layout, as I saw the Youtube videos over a year ago now. It is indeed impressive. I counted 113 turnouts (including diamonds and slips) on that layout, although I may be off by one or two.

 

If one is using this to calibrate the rate of progress that I am likely to make on this layout, that does not seem to be plausible, as that would suggest a rate of one turnout every 3 months on average for the last 30 years (installation and wiring; I use turnout count rather than linear meters as I do not have the measurement of the trackage on that layout in linear meters). I note that it is an analogue which would make the wiring on a larger scale layout more complex than it would be in DCC (not that DCC wiring is not capable of being complex). This seems to be entirely out of line with the other data point so far available, and we do not know how intensively that this was worked on over that time: there might have been gaps decades long with no work at all.

 

In relation to curve radii, the data by those who have very helpfully tested on this thread suggests that this is not an insurmountable obstacle, although it does pose challenges and may require extra adhesion on some locomotives.

 

In relation to baseboards, as I have stated previously, I intend to have these made professionally, as I do not have any skill for woodwork, so the difficulties of the baseboard construction would not of themselves be something with which I need directly concern myself. I do not think it practical to attempt to make this layout modular or portable.

 

In relation to a pulley system for the possible N gauge layout, this seems to be fraught with difficulty. If it were achievable within reasonable parameters, that would be potentially attractive, but I do not know whether the roof could support the weight, whether it would be too awkward to use, whether a sufficiently reliable system could be devised, or whether the equipment would need more clearance than is reasonably available.

I mentioned in a previous post that I have a gradient on my Branch. Though my kitbuilt locos manage this with ease, purely out of interest, I yesterday ordered a pack from powerbase which I'm going to install. Once laid, I'll post some comparisons with off the shelf locos with and without magnets. From some of the feedback i've read around the internet, it may or may not be as good as claimed by the manufacturer.

Regarding timescales, turnout count is not in anyway a reliable form of measurement. There are far more aspects to building a layout than laying points. Laying cork (or whatever) and creating a perfect roadbed is time consuming. Laying plain track can take a surprising amount of time if you want to get it right, then there is ballasting, now THAT takes forever to do a proper job. The list goes on. though in the case of Kings X the build time also includes rebuilding and improvements.

Edited February 28, 2018 by Denbridge

[Denbridge]

The reason that I am trying to calculate how long that building the layout will take is because it has been suggested that building the layout will take a long time and that I should take that into consideration when choosing what sort of layout to build. I need to be able to quantify that to some extent to be able to make any meaningful decisions based on it.

 

In any event, I have now further revised the layout design. For some reason, I cannot attach files, so I have had to upload them to a server. Here is the revised upper level:

 

 

and here is the revised lower level:

 

 

As you will note, I have moved the engine shed to the far corner of the layout. I was concerned about reach/access distances, but, by altering the station throat layout and moving the lower level station back, I have been able to achieve the recommended 900mm front to back reach distance in the engine shed area. This has allowed for a slightly larger engine shed and one with more direct access to the station throat without conflicting with the carriage sidings.

 

I have also shortened the platforms a little: the longest pair of platforms can still take 12 carriage trains (indeed, it could take a 13 carriage train, but that would not fit in the carriage sidings), and the next longest two pairs of platforms can take 11 carriage trains. The carriage sidings has one road that can take 12 carriages, and the others (bar the short one) can take 11 carriages.

 

Moving the depot has enabled me to straighten the fiddle yard sidings as recommended, which are shown on the plan. I have also altered the layout of the fiddle yard so that the main line trains run around the outer reversing loop whereas the relief line trains run around the inner reversing loop. I have extended the length of the fiddle yards slightly so that the ends of them will oversail the workbench a little more, but at ~1.2m in height, this should not be too much of a problem. I have also slackened the curves at the left hand side of the layout plan.

 

The result of all that is that trains on the main lines (as opposed to the relief lines) and in the carriage sidings never have to negotiate a curve of less than 572mm radius (4th radius in Hornby/Setrack terms), and never have to negotiate, even in the fiddle yards, short radius points. Trains on the relief lines in the fiddle yards must be able to negotiate 3rd radius curves and short radius points, but an express train dispatched from the station onto the relief lines for any reason can cross onto the main lines before circumnavigating the reversing loop. Short and medium radius points are, as before, confined to the fiddle yard/non-scenic areas. Only trains using the lower level will have to negotiate 438mm (2nd radius equivalent) curves and only trains passing between the upper and lower levels (via the helix) need to traverse any sort of gradient. Trains using the lower levels will either be electric stock or tank engine hauled suburban stock with trains no longer than 6 carriages, which (perhaps with a bit of magnetic assistance on the helix) should be able to manage the tight curves from what I have been able to discover so far.

 

Hopefully, with the long trains (whether in the sidings or on the main line) no longer having to traverse any curve of <572mm, it should not be necessary to use magnetic assistance other than on the helix, and only a limited range of stock will need to use this.

 

This revised plan is still usable with GWR stock owing to the ability to use 12 carriage trains. It remains a "track heavy" layout, but that is really a matter of taste rather than practicality. Moving the depot does not allow the town scene that I had imagined, but has helped to solve a lot of practical issues with the previous version, so it is probably worthwhile.

 

If I take a fancy to Midland/LMS/ex-Midland stock in the future, I could always just switch out the stock on this layout and have a whole new operating experience. (Indeed, one might even do the same with the LNER/GNR, as that, too, had a connexion to the City Widened Lines).

 

In any event, I should be grateful for any feedback on the revised plan. Your feedback so far has been most invaluable.

The redrawn plan is certainly a great improvement, but aside from other issues, you still have the impossible helix. The gradient to get it under the terminus on the first level drop will be impossibly steep, combined with a radius that is far too tight, no amount of weight and powerbase magnets will help. In the space you have available, I just don't see how you can ever make this aspect work. Another point that may be worth considering is motor and drive train wear. Modern models are notoriously fickle. a trawl of the internet will show hundreds of tales of woe. You may well be asking too much of the models you buy, with expensive consequences.

[Dagworth]

James, with all your questions about how long things take, can we turn it around?

 

How long do you want to spend building the layout?

 

Andi

[Denbridge]

As you will note, I have moved the engine shed to the far corner of the layout. I was concerned about reach/access distances, but, by altering the station throat layout and moving the lower level station back, I have been able to achieve the recommended 900mm front to back reach distance in the engine shed area. This has allowed for a slightly larger engine shed and one with more direct access to the station throat without conflicting with the carriage sidings.

 

How do you address reaching the furthest tracks at the terminus end? Especially once platforms, canopies Lamposts etc are in place, you risk a demolition job just doing track cleaning (which can't be reliant on track cleaning gizmo's. Track at terminal ends gets more dirty, simply because there is less movement on it) And no matter how well laid the track is, you will get derailments. 400+mm is a hell of a REACH.

As you will note, I have moved the engine shed to the far corner of the layout. I was concerned about reach/access distances, but, by altering the station throat layout and moving the lower level station back, I have been able to achieve the recommended 900mm front to back reach distance in the engine shed area. This has allowed for a slightly larger engine shed and one with more direct access to the station throat without conflicting with the carriage sidings.

[Harlequin]

@James: Where does the GWR 12 carriage train formation requirement come from? That is one of the things that is seriously impacting on your design, it seems to me.

 

I found this: http://www.rmweb.co.uk/community/index.php?/topic/84395-sample-wr-train-formations-from-the-age-of-steam/

which suggests that mainline passenger train formations in and out of Paddington were quite variable and the most common in this list was 10 vehicles long.

Edited February 28, 2018 by Harlequin

[Denbridge]

@James: Where does the GWR 12 carriage train formation requirement come from? That is one of the things that is seriously impacting on your design, it seems to me.

 

I found this: http://www.rmweb.co.uk/community/index.php?/topic/84395-sample-wr-train-formations-from-the-age-of-steam/

which suggests that mainline passenger trains in and out of Paddington ranged from 7-12 and the most common formation was 10 vehicles long.

Depends a lot on the Era and the time of year. In the mid 30's some summer trains would load to 15 coaches 

[The Stationmaster]

On the latest plan I see there is one terminus platform which has no access to/from the carriage sidings.

 

Incidentally as far as I can work out from the baseboard width you gave that helix is going to have a radius of 18 inches at most if it sits inside a baseboard width of just over 1metre - that is going to result in a very steep climb.  Have a look at the US info on helixes as linked  by Dagworth - they contain some very sound advice based on experience.

[jamespetts]

Thank you all for your ongoing feedback on this: it really is most helpful. The tight helix seems to have been the most important problem with the last design. I have found that, by adding a small bulge to the baseboards near the end of the shed, I can have a 3rd/4th radius helix offset sufficiently from the reversing loop on the other side of the room to allow (just about) sufficient space to pass between the two sides of the layout, with judicious angles used in the baseboard outline.

 

I have thus produced a revised plan. Here is the upper section:

 

 

and here is the lower section:

 

.

 

I have also made some other minor changes: I have added an extra road to the engine shed, and altered the sidings around the engine shed a little as I was having trouble working out how the locomotive coal train would be shunted in the previous arrangement (the pilot engine would have had difficulty running around the locomotive coal train's brake van in the engine shed area). I have also added three auxiliary storage sidings in the fiddle yards so that rarely used trains (such as the locomotive coal train) can reverse into them and then be stabled out of the way to give some extra storage space. Finally, I have added an extra crossing in the carriage sidings to allow one pair of carriage sidings to be used more readily for dividing/combining shorter rakes of carriages/loose carriages/strengtheners.

 

Denbridge - I should be very interested in the results of your branch gradient PowerBase tests. Your previous tests were very useful and interesting.

 

Thank you for the information on GWR carriages. I think that that is broadly in accordance with what I had imagined the position to be from what I had been able to find out so far.

 

In relation to the tracks at the back of the terminus, save for those which descend into the now enlarged helix, the furthest reach is ~1.0m just opposite the new bulge (which might only be on the lower level), otherwise 950mm for most of the length of the station. Since these boards will be lower (1.2-1.3m high, depending on whether I can build an N gauge layout above it; I will respond to the suggestion regarding the shelf in the N gauge layout thread), this should not be beyond my ability to reach. I will have to make a note to make sure to make any overall roof removable.

 

In relation to a platform without access to the carriage sidings, I have checked the plan, and cannot find such a platform. Can you let me know which one that you think that it is?

 

As to the descent to the helix, this is intended to start almost immediately after the junction, and that gives me a <2% gradient on the upper level, which should look realistically shallow as well as be reasonably easy for the trains to negotiate.

 

In relation to building time, it is very difficult indeed to know what to do with imprecise information. If there is not a linear relationship between any given measure of complexity/size and build time, then I might as well build a large layout rather than a small layout, as there may be little (proportionate) difference in build time between the two. The only precise information that I have suggests a manageable ~177 hours of work to complete the track laying and wiring of the upper level. As to how long that I should like to spend building it - that is hard to answer. In one way, it would be splendid to be able to summon elves to build it all in the twinkling of an eye and have it up and running instantly; but on the other hand, I suspect that I should then be missing a certain joy of building it myself and seeing how all the components fit together, planning the logic of the wiring and so forth. The testing, too, I imagine will be most interesting.

 

In terms of data, I am looking at some well known model railway Youtube channels. Dean Park is a good example: he started in June 2012 according to his first video posted in December 2012, by which time he had completed the baseboards and a single circuit of track, together with most of the tracks for the station. Later in December, by the second video, he had completed the second loop. By March 2013, the basic track layout had been completed and he had started work on the platforms. The ballasting and scenery appear to have been largely complete by October 2014, albeit the layout was further refined for sometime afterwards.

 

I looked at the videos of the original Everard Junction, but the first video shows the track already in place, so there is no good data point for this layout, and the current layout has not been completed, although I note that what appears to be a gargantuan 14 road fiddle yard has now been laid, corked and wired (at least so far as the droppers are concerned). He described that as having taken a long time, stating that he started work on the fiddle yards "shortly after" completing the back scenes in his previous video. That earlier video was posted on the 5th of December 2017.

 

Silver Sidelines - you suggest that using DCC will make hauling trains up gradients more difficult than with analogue. Can you elaborate on why this should be? I have not heard of this issue before. The videos show a Hornby BR 8p and 7 carriages managing a gradient on a curve (albeit slowly), although it is not clear what the gradient or the curve is from the video. I was not planning on having trains longer than about 6 carriages (or the equivalent length in wagons) using the helix. Hopefully, this should be manageable with a 3rd/4th radius helix (although unfortunately the upward direction will have to be the 3rd radius).

[Dagworth]

 

I was not planning on having trains longer than about 6 carriages (or the equivalent length in wagons) using the helix. Hopefully, this should be manageable with a 3rd/4th radius helix (although unfortunately the upward direction will have to be the 3rd radius).

Please look at the link I posted regarding helix radius from the American site (who have far far more experience of helices than we do in the UK)

He found that a 24" radius helix was still far too tight. Your 4th radius is still an inch and a half below this! 

 

Buy a circle of 3rd radius track and a set of Hornby inclined piers (http://www.hattons.co.uk/7264/Hornby_R658_Set_of_inclined_piers/StockDetail.aspx) and make a dummy helix - or try using books or CDs or something to act as supports. The Hornby supports only go up to 80mm, your helix will probably need to be up to 100mm so you will need a couple of bodge supports at the top end...

Now try your train climbing it from a standing start. 

[jamespetts]

Dagworth - I am not sure that that is right: I have seen a number of examples of successful 3rd/4th radius helices (for example, this one, showing a locomotive haul a train of 14 freight wagons up such a helix and start from a stand without incident).

 

The American forum was discussing helices for very long trains (as is common in US model railroading, seeking to model the very long freight trains that are common in the US; that thread referred to trains of 20 cars' length). The point about "stringlining" appears to be common to all tight turns for very long trains and is not specific to helices. Since I intend to be operating short trains on this helix, it does not seem to be immediately relevant. Do you have any experience of helices yourself, or are you going on what is posted in the forum threads to which you referred? If you do have personal experiences of helices, I should be very interested to learn more about them.

 

Edit: I notice the following from the US forum thread:

 

 

 

20" radius would be a problem unless your comfortable with only running short trains. Grades pretty steep too, but would work with the short train thing.

.

 

For reference, 20" is 508mm, whereas 3rd radius is 505mm.

Edited March 1, 2018 by jamespetts

[Dagworth]

Dagworth - I am not sure that that is right: I have seen a number of examples of successful 3rd/4th radius helices (for example, this one, showing a locomotive haul a train of 14 freight wagons up such a helix and start from a stand without incident).

 

The American forum was discussing helices for very long trains (as is common in US model railroading, seeking to model the very long freight trains that are common in the US; that thread referred to trains of 20 cars' length). The point about "stringlining" appears to be common to all tight turns for very long trains and is not specific to helices. Since I intend to be operating short trains on this helix, it does not seem to be immediately relevant. Do you have any experience of helices yourself, or are you going on what is posted in the forum threads to which you referred? If you do have personal experiences of helices, I should be very interested to learn more about them.

I will refer you to http://www.rmweb.co.uk/community/index.php?/topic/66572-millfield-a-helix-build-in-progress/?p=906154 from that topic. Bear in mind that Bachmann 37 has 6 driven axles!

 

 

I've got huge amount of experience of tight gradients and long trains, not helices specifically but steep enough to have needed to triple the weight in Lima diesels (with traction tyres) to get up the slope. And that was only climbing 70mm of vertical height. Ask any of the team who ever operated Dagworth, they will all tell you that the gradients were too steep and they were shallower than you are proposing.

 

Andi

[mightbe]

The platform in question is the 5th from the top. There's a single slip that needs to be a double slip.

 

Everyone has been trying to help but you keep rejecting sound, well-founded advice--a charge raised and denied multiple times--usually on the basis that you haven't been presented with "the data". This dogged insistence on empiricism is counterproductive, and you needlessly challenge decades of practical experience. The path has already been well-cleared, and yet there's a question mark around the perceived negativity.

 

As for the helix-- you've posted a link showing a heavy, six-axle diesel going up a very tight helix but you propose a layout set in the 1930s. It's a comparison between apples and root vegetables. It's also worth bearing in mind that your helix goes the "wrong way" insofar as the shallower gradient is descending while the steeper gradient is on the ascent (the linked helix goes the 'better' way around).

 

Quentin

[Harlequin]

You need 65mm clearance from baseboard to potential obstructions above for OO vehicles on Peco Streamline code 75 track. And that's very tight - most people would want 75mm clearance at minumum.

 

The following drawings are to scale, assuming that the blue outline on your top level drawing is 7500mm wide.

 

The 1:50 gradient starts at datum point X straight after the junction turnout, without any transition into the gradient, which you would have to provide in reality.

 

Zoomed in on the area of interest:

 

This is all just indicative because we don't know the actual construction of the baseboards but I have suggested 9mm ply and 50mm support framework, which most people would consider to be minimal.

 

The train cross-section symbols are 60mm high including track. I have measured one of my own locos to get this figure.

 

You can see that the trains reach the helix barely passing under the ply surface and you would have to avoid having any baseboard support framework above the helix at this point.

 

The same applies to the point where the helix passes under the top platform line, which is only 7.4mm lower (assuming the helix gradient is also 1:50).

 

You might argue that the helix is steeper or that I've shown it in the wrong place but adjusting either of those things will only change the results by millimetres.

 

And remember that I haven't made any allowance for the track to transition smoothly from level running to the gradient, which will decrease the clearances at the helix end.

 

BTW: Do you need a double track helix? Are you ever going to run trains up and down at the same time?

Edited March 1, 2018 by Harlequin

[Denbridge]

You need 65mm clearance from baseboard to potential obstructions above for OO vehicles on Peco Streamline code 75 track. And that's very tight - most people would want 75mm clearance at minumum.

 

The following drawings are to scale, assuming that the blue outline on your top level drawing is 7500mm wide.

 

The 1:50 gradient starts at datum point X straight after the junction turnout, without any transition into the gradient, which you would have to provide in reality.

JP OO 5.png

 

Zoomed in on the area of interest:

JP OO 5b.png

 

This is all just indicative because we don't know the actual construction of the baseboards but I have suggested 9mm ply and 50mm support framework, which most people would consider to be minimal.

 

The train cross-section symbols are 60mm high including track. I have measured one of my own locos to get this figure.

 

You can see that the trains reach the helix barely passing under the ply surface and you would have to avoid having any baseboard support framework above the helix at this point.

 

The same applies to the point where the helix passes under the top platform line, which is only 7.4mm lower (assuming the helix gradient is also 1:50).

 

You might argue that the helix is steeper or that I've shown it in the wrong place but adjusting either of those things will only change the results by millimetres.

 

And remember that I haven't made any allowance for the track to transition smoothly from level running to the gradient, which will decrease the clearances at the helix end.

 

BTW: Do you need a double track helix? Are you ever going to run trains up and down at the same time?

Phil, nice work. Hopefully James will now realise why the Helix won't work. 

James, You have made great strides with improving what has the potential to be a good design. If you now realise the Helix won't work, you have the potential to make it even better.