Dublo 3 Rail Layout

Hi Britrail, I experimented with this last year, the big issue I found was getting sufficient swing on the coupling to mimic a Dublo wagon fitted original.

I am a fan of the generally disliked original bulky plastic Dublo coupling which despite its bulk is IMO the most efficient and reliable Dublo coupling, it is also the one that most easily lends itself to making with filament based 3D printing.

My tightest curved track radius is approx 15 inches and so long as the other wagon has a free enough swing the pivot part of the NEM socket swings sufficiently for it to function reliably. However the minimum radius of Dublo tinplate track I suspect is much smaller.

My intention is to revisit these couplings using a printer capable of printing at higher resolution in the near future and possibly print the dovetail of the socket so that a swivel can be included.

Last years work can be found here.

Jim

 

Many thanks for your reply Jim ! According to the HRCA site "standard curves were of 15 inch radius, 8 to a circle. From 1940 a large radius 17.25 inch curve was available, allowing perfect double-track curves at the standard spacing of nominally 2.25 inches"
So your couplings would be OK for 3-rail. If you ever get around to producing them in any quantity I'd me most interested to try a couple of pairs.

 

I've never seen anyone selling repro 3-rail track, but the original is still plentiful because HD produced so much of the stuff over the years, there are rarer items of course - notably the very short straights and curves - quarters and especially eighths. I've tried a bit of Marklin track. It works with the "spoon" pickups, if a little noisy, but the plunger pick ups get stuck on it, so I keep a lookout for early Marklin M track which did have a continuous centre rail like HD, but it doesn't come up for sale very often.

 

Thanks, I would probably get them produced for sale through a 3rd party like Shapeways, 3D printing is a slow process and it's too late in the day for me to consider quantity production myself, too much on my 'bathtub' list, however whether they could made at a price which would sell is another issue altogether. I get the impression that if there was a market for selling a few 100 pairs then there would already be some available, but may be not.

This also applies to the vintage parts I have developed for the Arkitex 00 system, these old toys really appeal, and what makes 3D printing worth the effort for me is being able to just print the parts I want, especially custom parts now that I have built up a catalogue of components and, have just about got the geometry of the system reverse engineered correctly at last. Then there was how to translate them into something that is printable and usable.

Jim

 

Most interesting. Keep us posted Jim if you work on this subject again.

 

If you need a beta tester I’m your man

 

Thanks Andy, sounds like that they are cutting corners at the design creators expense, if your 7mm models are becoming undesireable my 4mm parts would probably not be acceptable to them either. I presume you print and sell directly now?

Perhaps they are finding that the time it takes to print some designs is eating away at the bottom line, or perhaps they are just being more selective, that is cherry picking easy items to print to maximise profit.

The problem with my parts, particularly the Arkitex 00 range is that quite a few of any one part would be required by an 'enthusiast' and with e.g. some panels taking between 30 and 45 minutes to print an order of even 10 panels requires a lot of printing time, but I am probably safe there, as in practice despite the modest number of views and my postings rising on Google thanks to P1MRC it's a niche too tight. Anyway, not a problem as I am not doing it for profit, I am doing it out of personal interest.

Simplex couplings to fit NEM sockets may have a small market, but so far only one person (Britrail) has asked about such items, but once again these are personal interest items, if a demand arises then I will consider delivering it.

Jim

 

Noted Wolseley, Jim

 

Edit:
Great minds clearly think alike Mr Wolseley . I’d only just posted this when yours came up. We must’ve been writing them at the same time!

I’ve had this 2-rail "Gronk" sitting a round for a while now.

I’d been wanting to do this since I picked up this one here in France last year, but I didn’t want to do anything permanent and didn’t want to mess up a perfectly good 2-rail model.
The original plan was to use the 3-rail pickup unit from a dead 0-6-2T I had lying around, but everything I read about such conversions warned of poor running due to the fact that the insulated wheels would only return on one side. Solutions such as using conductive paint have been used by others with mixed results.
I figured that ideally the 2-rail pick up would need to be retained. But how ?

This is the solution, the wire from this Marklin slider shoe is simply passed up through the hole in the chassis. The two rail pickup wire is cut, lengthened and soldered to the brush holder. The wire from the motor is soldered to the wire from the skate. Then some insulating tape is cut and stuck onto the pick up plate and the Marklin skate is positioned and superglued in place on the tape.

The result us an easy to reverse conversion and a very smooth running loco. It only took about 30 minutes to do. Writing up, posting and editing this has taken longer than the conversion!
"Coughs and sneezles, spread diseasels" as a certain GWR tank engine once said.