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TEMPLOT 3D PLUG TRACK - To get up to speed with this experimental project click here.   To watch an introductory video click here.   See the User Guide at Bexhill West.

  • The Plug Track functions are experimental and still being developed. Some of the earlier pages of this topic are now out-of-date.

    For an updated overview of this project see this topic.   For some practical modelling aspects of using Plug Track see Building 3D Track.

    The assumption is that you have your own machines on which to experiment, or helpful friends with machines. Please do not send Templot files to commercial laser cutting or 3D printing firms while this project is still experimental, because the results are unpredictable and possibly wasteful.

    Some pages of this and other topics include contributions from members who are creating and posting their own CAD designs for 3D printing and laser-cutting. Do not confuse them with Templot's own exported CAD files. All files derived from Templot are © Martin Wynne.
  • The Plug Track functions are experimental and still being developed.

    For an updated overview of this project see this topic.   For some practical modelling aspects of using Plug Track see Building 3D Track.

    The assumption is that you have your own machines on which to experiment, or helpful friends with machines. Please do not send Templot files to commercial laser cutting or 3D printing firms while this project is still experimental, because the results are unpredictable and possibly wasteful.

    Some pages of this and other topics include contributions from members who are creating and posting their own CAD designs for 3D printing and laser-cutting. Do not confuse them with Templot's own exported CAD files. All files derived from Templot are © Martin Wynne.

What thickness of trackbed do you use?

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Martin Wynne

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Having recently acquired a toy CNC miller, I'm now beginning to prefer the one-piece timbering bases in MDF or plywood, rather than the FDM 3D-printed option for Plug Track. This is EM gauge in MDF -- at this stage you have to imagine the ballast between the timbers: :)

index.php

(The through holes are from some sockets on the other side of this bit of MDF.)

It's faster than the FDM printer, and the work area is significantly larger, and can be extended with expander kits. Unlike a laser-cutter the machine cost is comparable with an FDM printer. The only downside is that the process very noisy. More info:

https://85a.uk/templot/club/index.php?threads/cnc-milled-timbers-instead-of-laser-cut.276/

MDF doesn't have any actual grain of course, but when stained it has a pleasant wood-like surface texture which at normal viewing distance represents railway timbers very well. And unlike FDM printing you get sharp corners on the timbers.

But the most significant advantage is that it needs only a 2-D DXF file from Templot, which makes it much easier to envisage complex bespoke pointwork done this way. In fact existing BOX file projects could be used almost as-is for the 2-D exports (likewise for laser cutters). Including the automated tandems and slips:

chaired_slip.png


It just needs changes in the code to put the right chairs in the right places. The BOX file doesn't need to change -- or any changes needed can be automated.

Whereas for the 3-D exports (for FDM printed timbering bricks) any complex Templot designs are likely to need some significant re-working to any shoved timbers and partial templates, to create a usable 3-D file.

Also of course, the idea of a solid one-piece timbering base is very appealing. Just plug in the chairs and rails, and screw it down to the baseboard. No messy gluing or weighting down, no templates or gauging. If the alignment is a bit out, just slacken the screws and adjust it. :)

Which brings me to the actual subject line of this topic. Matching the level of such a one-piece base to adjacent flexi-track or other tracks. The above was cut in 3mm MDF. If you use 0.8mm ply timbers, that's going to need 2.2mm of trackbed underlay to bring the timber tops to the same height. If you use thicker 1.6mm timbers, only 1.4mm of underlay is needed. Neither of those are very convenient available thicknesses of cork. Nor are they thick enough to provide a proper ballast shoulder or cess.

It might be better to pack such a timbering base with card or foam to bring it to a more convenient height for the adjacent track. And/or use thicker MDF in the first place?

Just thinking aloud -- I've rather lost touch with current tracklaying practice and available trackbed underlays and thicknesses.

When I first thought of 3D track direct from Templot it seemed that the major issue would be the chairs. As it's turned out, the little Elegoo 3D printers work great, and the chair designs are all doable, if time-consuming. It's the timbering which has proved more problematic, with a lot of ifs and buts and alternative options.

Because after all that, you still need the FDM printer for the filing and bending jigs -- the CNC miller would hardly be strong enough for those. As I said, too many ifs and buts.

Martin.
 
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On my current (non-experimental) project I am using 2mm thick greyboard for the trackbed, onto which I am glueing the printed Templot designs, and then either 1.6mm plywood sleepers, or 1.6mm PCB (for board ends), with Exactoscale chairs. These match up with some of Wayne's Finetrax OO-SF turnout kits.
 
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On my current (non-experimental) project I am using 2mm thick greyboard for the trackbed, onto which I am glueing the printed Templot designs, and then either 1.6mm plywood sleepers, or 1.6mm PCB (for board ends), with Exactoscale chairs. These match up with some of Wayne's Finetrax OO-SF turnout kits.
@Steve_Cornford

Thanks Steve.

So that's 3.6mm to the timber top? My 3mm MDF bases would therefore need 0.6mm card packing to match. Thanks for the info. :)

Martin.
 
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Hi Martin,
What thickness should one be aiming for?
@Steve_Cornford

Hi Steve,

It's the usual piece of string question. However sleepers are 5" thick and timbers are 6" thick, and for a running line you need at least 6" of ballast below them, so on plain track in open country you are likely to see a ballast shoulder at least 12" (4mm) deep from the sleeper tops, sometimes a lot more:

no_weeds_1120x800.jpg


mt_pleas.jpg


2_031551_430000000.jpg


That's from the ballast top to the underlying formation. The cess is then beyond that, and in cuttings might be a lot deeper for drainage. This is how Templot draws the templates:

2_060536_020000000.png


2_071626_150000000.png


Within stations and junctions, there is frequently no obvious ballast shoulder between the tracks. Yards and sidings don't need much depth of ballast below them, so often there isn't much visible shoulder there either.

Generally if you use a thick trackbed you can build the ground up where a deep shoulder isn't needed, but with a thin trackbed on a solid baseboard it's difficult to model track in open country convincingly.

cheers,

Martin.
 
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Martin

My main concern with this method would be track noise, I use 3mm closed cell foam and flexible glue (Latex). But I guess nothing stopping these panels being stuck on to foam
 
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But I guess nothing stopping these panels being stuck on to foam
@Hayfield

Thanks John.

Yes, I did mention packing the panels with card or foam. Finding the right thickness is a bit tricky.

If you are using 3mm foam and 1.6mm timbers, that makes a timber top of 4.6mm, say 4.7mm with a layer of latex adhesive.

So using 3mm MDF panels would need 1.7mm packing to match. No such thickness of foam seems to be available, but 1/16" self-adhesive cork would get close with the adhesive layer:

https://www.amazon.co.uk/gp/product/B07623C35L

Alternatively, using 4mm MDF with this self-adhesive felt might be worth a try -- it would probably iron thinner:

https://www.amazon.co.uk/dp/B08ZSJTHPB

If cork or felt was applied to the MDF before machining it might make the process a bit quieter too.

Lots of ideas to try. :)

cheers,

Martin.
 
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Martin

My main concern with this method would be track noise, I use 3mm closed cell foam and flexible glue (Latex). But I guess nothing stopping these panels being stuck on to foam
Hate to say it but - me too! (Just for the record)

Richard (and Mylo) on the train home after a morning in Lincoln.
 
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Generally if you use a thick trackbed you can build the ground up where a deep shoulder isn't needed, but with a thin trackbed on a solid baseboard it's difficult to model track in open country convincingly.
@Steve_Cornford

p.s. Just to add that a thicker trackbed also allows you to replicate a very common, but seldom modelled feature. Sidings and yards alongside running lines are often at a lower level than the running line. This makes gravity a safety feature in addition to the trap points. Here you can see a ballast shoulder about 12" deep from the running line down to the siding. But with no obvious shoulder between the siding and the open yard. It's likely that the underlying formation is flat across the whole site. The running line gets a good depth of ballast below it, but the siding got very little, or none:

dent_siding_1973_1280x720.jpg


Martin.
 
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Hate to say it but - me too! (Just for the record)

Richard (and Mylo) on the train home after a morning in Lincoln.

Do we need something like this across the baseboard before adding any track:

https://www.amazon.co.uk/dp/B089QRFZCT

On Adavoyle Junction, Tony Miles added a layer of Sundeala softboard all over the baseboards before adding the cork trackbed. It was left loose and only lightly pinned to the baseboard. I don't recall any noticeable noise problems. It also made it easier for the scenic department to excavate into the baseboard surface where needed:

aj_construction1.jpg


I believe Sundeala is made from recycled newspaper:

https://sundeala.co.uk

Is Mylo keen on railways?

cheers,

Martin.
 
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A thought. Aren't there health hazards associated with milling MDF? Just wondering.
Nigel

Hi Nigel,

There are, although not necessarily much worse than cutting other composite boards such as chipboard and plywood. Or hardwoods.

But it's hardly in the same category as nuclear waste. I think the harmful ingredient is formaldehyde, which I remember sloshing about in the biology lab at school (formalin). :)

In any event, I have harnessed Henry to the CNC, using a redundant vacuum hose, and he does a good job of hoovering up the sawdust. He is fitted with HEPA-rated bags.

https://www.epa.gov/indoor-air-quality-iaq/what-hepa-filter-1

index.php


cheers,

Martin.
 
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@Steve_Cornford

Hi Steve,

Found another view of that siding, showing the ballast shoulder more clearly:

dent_siding2_1973_1280x720.jpg


Dent, September 1973.

cheers,

Martin.
 
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Do we need something like this across the baseboard before adding any track:

https://www.amazon.co.uk/dp/B089QRFZCT

On Adavoyle Junction, Tony Miles added a layer of Sundeala softboard all over the baseboards before adding the cork trackbed. It was left loose and only lightly pinned to the baseboard. I don't recall any noticeable noise problems. It also made it easier for the scenic department to excavate into the baseboard surface where needed:

View attachment 2579

I believe Sundeala is made from recycled newspaper:

https://sundeala.co.uk

Is Mylo keen on railways?

cheers,

Martin.

Hi

That's the idea with taking Mylo on the odd train trip - this was his second, and I suspect I'd left it too long between the two trips, as he started off on the train scared, then interested, then slightly bored. On the way back, he had lunch (I didn't :-( then promptly fell asleep. The trouble at this stage is that once we get anywhere, we shouldn't do too much walking (although playing in the garden all day is "allowed") - so we had a quick walk to a dog friendly cafe, a coffee, and a quick wander around the park. He's just taken himself off to bed.

I forgot to mention, I would like to use 2mm thick walnut for my sleepers and timbers (Cornwall model boat), but I wonder if I'll "run out of life", and the CNC MDF route might make life easier.

All the best

Richard.
 
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A very interesting topic.
I personally plan to have a base of 4/5mm thick floor insulation foam sheet as a base for all track work (to aid in noise reduction) then running lines will have a 3mm thick underlay/cork bed and 1.5mm sleepers & Turnouts (I cannot readily obtain exact 1.6mm ply sheets (cost effective), I could try gluing 1mm + 6mm sheets but not sure it's worth it) In future maybe.
In Yards I will negate the 3mm underlay and simply lay direct to the original 4/5mm board to represent the height change. Mixed with 2mm ballast and dust/ash/general dirt and grime I'm sure it can be a convincing and accurate representation.

Thoughts?

Cheers,
James
 
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and 1.5mm sleepers & Turnouts ... ... Thoughts?
@LittleWestern @Steve_Cornford

Hi James,

The Plug Track chairs currently need a sleeper/timber thickness of 3mm or 1/8". That's to allow sufficient lead-in taper on the plug depth for them to be easily located in the sockets before pressing home. Originally I tried shorter plugs in shallow sockets with very little lead-in, but I found it very fiddly to space them along the rail and keep them all properly aligned with their sockets while firming the rail home. Having deeper plugs with a lead-in keeps them all started in their sockets, making the process 10 times easier.

Steve's plan is (or was?) to have a double layer of 1.5mm ply, with just the sockets cut into the lower layer to create sufficient clearance for the plugs. To save laser-cutting and material costs, it would be possible to omit the lower layer and lay 1.5mm timbers on longitudinal battens -- reverting to the old way of building model track:

track_on_battens.png

For plug track it would need 2 narrow battens under each rail, with a gap between them for the bottom of the plugs. All lost under the ballast, as for the FDM bases. The edge guide and spacer wouldn't be needed if the timbers are laser-cut with the sprues option.

If you go for an all-loose-jaws option, the chairs are inserted and pressed into the sockets one at a time. This would make it much easier to align each one, and maybe a 1.5mm plug would be more easily doable. However, the locking process for the loose-jaw does rely on a longish depth of pin and slot to hold firm. So for shorter plugs the pins might need a smear of cyano.

All these dimensions can be set using the controls on the DXF export dialog. There is still a mass of practical experimenting to be done to arrive at the best way of building plug track, with much trial and error. No-one can really get started on that until I have got more of the chairs done, and at least a full turnout is possible. Guess what my New Year resolution is? Don't ask about last year's. :)

cheers,

Martin.
 
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Hi @Martin Wynne
So firstly, I wasn't planning on using plugtrack, but having read up more on the subject this morning and reading your reply above, the principles you have descirbed I had not originally taken into consideration.

Discounting the 5mm foamboard base (noise reduction purposes)
For Mainline and Branch running lines, going off data provided, 12" (4mm) from sleeper tops should be sufficient correct? So the 1.5mm Sleeper + 3mm trackbed convered (with shoulders trimmed to a sloped angle) with ballast should give a visibily accurate ballast shoulder no?
In your sketch, it demonstrates if the modeller was using plugtrack without a dedicated track bed no? Meaning that the perpendicular 1.5mm wood runs provide said trackbed.
Am I understanding this correctly? If not please forgive me :D

Cheers,
James
 
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@LittleWestern @Steve_Cornford

Hi James,

A couple of points:

It's not my sketch -- it's scanned from a 1949 book about model railways.

Templot is a workshop tool. You set it to create whatever dimensions you want.



If I was using laser-cut 1.5mm or 1/16" timbering in 4mm/ft scale I might adopt something like this:

track_on_battens2.png


The longitudinal battens are 4mm x 1.5mm stripwood or plywood. Easily available as 4mm timbering strip for plywood pointwork construction from the usual suppliers. Or as limewood strip from model boat suppliers. Or cut from 1.5mm mounting board. Or if you have a sawbench easily cut it yourself -- the exact width is unimportant.

That gives a total clearance depth for the chair plugs of 3mm or 1/8".

Depending on cost, you might prefer to get the timbers cut in 3mm plywood, which eliminates the need for the battens.

As can be seen, the plugs could be reduced in depth to 1.5mm, eliminating the need for battens, but in that case I don't think the loose-jaws as shown would be feasible -- you would need to get the key past the rail head and locate the pin in the slot both at the same time. No fun at all. The long-pin design works because the pin is already inserted in the slot before the jaw is pressed all the way down, clipping the key under the rail head in the process.

But if the solid jaws are adopted instead of loose jaws, the shorter plugs would be very fiddly to use because they must be accurately spaced out on the rail before they can be pressed home. It's 100 times easier if longer plugs are used, which can loosely locate themselves in the sockets before pressing home.

The ballast is then filled between the timbers. I would use 2 layers. A bottom layer of a course lightweight fill such as crumbled or broken cork. To cover all the between-timbers junk -- battens, wiring, stretcher bar mechanisms, screw and pin heads, etc. Then a thin top layer of scale ballast such as crushed walnut shells.

Ballasting is a lot easier if done without the rails in place. With solid jaws the ballasting can be done if preferred before fitting the chairs and rails -- taking care not to get any ballast below the sockets. For bash-fit chairs, the trackbed underlay would need to be firmer than soft foam.

With loose-jaws, the ballasting can be done before or after fitting the chairs, and before fitting the rails -- taking care not to get any in the pin slots. If using soft foam trackbed underlay, it would be better to bash-fit the chairs before laying the timbers.

Beyond the ballast shoulders you need some rough fill -- card, plaster, cork, etc., to represent the original prototype ground formation under the ballast -- for running lines at least 4mm below the timber tops and often more. This fill needs sufficient depth to leave a cess space before any scenic earthworks. Actual dimensions are very variable, refer to photographs.

I'm trying to stall answering questions in too much detail at this stage because at least for the plug track it is all still experimental and just theory. It will be much easier to answer questions when I have got more chairs done and started laying plug track in anger. I doubt the existing designs will survive contact with reality without change. :)

cheers,

Martin.
 
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Hi @Martin Wynne

Thanks again as usual for your brilliant explanations. I Must have misunderstood previously. I believe I have the original dimensions for timbers completely wrong for running lines!
Thank you for the illustration as well, it has opened my mind more. I believe I will aim for 3mm cut timbers on a 3mm track bed as you have shown. The ballast and such I have had much thoughts on using various mixtures of 2mm/4mm scale supplied ballasts mixed and weathered. However, I'm very interested in you stating the use of crushed walnut shells? I was not aware commercial ballast was made from walnut shells? As it happens I have 20kg of cracked walnut shells sat in my shed waiting to be composted :D perhaps I should dry them out!

I will take the considerations for Plug Track for the future, alas as I am modelling the GWR, as you have previously stated, this will come in time. I am using C&L and potentially Exactoslace printed chairs for all construction and am currently working on a tool to accurately place these before laying timbers. I have considered drawing something up to be laser cut however I have no access, and do not see access to a laser cutter for some time. At which point I will invest time in this. For now, a 3d printed tool to position a chair square on a timber at the correct gauge will do for now.

The idea of Plug Track is simply brilliant! I'm still wrapping my head around it! More reading needs to be done!

Many thanks,
James
 
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However, I'm very interested in you stating the use of crushed walnut shells? I was not aware commercial ballast was made from walnut shells? As it happens I have 20kg of cracked walnut shells sat in my shed waiting to be composted :D perhaps I should dry them out!
@LittleWestern

Hi James,

Crushed walnut shells make excellent model ballast. They are used for metal polishing and barrel tumbling for jewellery, crafts, engine parts, gunsmithing, etc., and as a gentle form of sand-blasting. And as a filter for some industrial fluids. Also used as a natural organic filler for some types of cushions and head-rests. Available from crafts shops and suppliers, and in the UK from Amazon:

https://www.amazon.co.uk/Crushed-Walnut-Shells-Available-kilograms/dp/B09718T769/

The usual prototype graded stone ballast mesh size is 1.5 - 2 inches, or 0.5mm-0.7mm in 4mm/ft scale. For which the fine grade is fraction too large, and the extra-fine grade is too small. A mix of the two sizes usually looks good. More of the extra-fine for old ballast, ash ballast in yards, etc. Less of the extra-fine for newly ballasted running lines.

See also this video about using crushed walnut shells:




p.s. Woodland Scenics web site says their ballast is made from "rock" (which is very heavy for deep ballast on a model).

cheers,

Martin.
 
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Thanks for the link to Amazon for the crushed walnut shells - never realised crushed walnut shells was a thing ... I used to use C&L's ballast which I think is also crushed shells. I think this is now sold by Phoenix Paint.

The walnut tree in the garden produced it's first nut last year ... and the squirrel got to it before I did ... although no lose to me, as I'm allergic.

Richard.
 
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Last edited:
Thanks for the link to Amazon for the crushed walnut shells - never realised crushed walnut shells was a thing ... I used to use C&L's ballast which I think is also crushed shells. I think this is now sold by Phoenix Paint.

The walnut tree in the garden produced it's first nut last year ... and the squirrel got to it before I did ... although no lose to me, as I'm allergic.

Richard.
@richard_t

Hi Richard,

For a large layout also available in industrial quantities:

https://edenproductsltd.co.uk/walnut-shell/

http://www.auraproductsltd.co.uk/product/walnut-shell/

Same with my cherry tree. "They just need one more day" - next morning not a cherry in sight after the birds had the same idea. :(

Martin.
 
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