Dublo Three Rail Tips

Thanks for the reply Gary.

I used XTrkCad(now free) to design a layout. It is probably completely un-rail-istic, but nevertheless it's what I wanted. {sorry couldn't resist}

I experienced the usual trials and tribulations with old 3 rail track and finally evolved a method of cleaning with the Dremel and it's wire brush b4 laying the piece.

Still there were faults. So I then employed an old Triang P4 controller... with the re-set button... to help me as I re-laid again piece by piece and isolated and remove the offending pieces, or at least repaired them after re-checking.

As I worked, occasionally I would employ an old Voltmeter, both for continuity checks and to see if any volts were passing through at all.

I encountered what I can only describe as a phenomenon, but you probably know all about. The track pieces would not be laid in isolation, despite the description of the points as isolating points. This led to a sort of a sub-topic in which I discovered that whilst Hornby list only isolating points or electrical (which it seems are not) points in their ancient catalogues, there are in point of fact two types of manual "isolating??" points... both wired differently.





I found that unless I rectified faults, which were apparent in seemingly unrelated bits... like sidings, then the whole loop wouldn't go. ??!!*£$%!!

The layout is controlled... if thats the word I want... by a gadget called an H&N duette, and what appears to be a sort of sibling H&N device which now manages the inner loop.
I retired the ancient Triang controller, and it's by-now indigenous wildlife... assorted creepy crawlies who had taken up residence in it's past, possibly in someone's shed... after achieving something approaching normal operation.
The track design from XTrkCAD is here...



Now confusingly, I am in the "interesting" position of being able to set off on my middle loop, transfer by points to the inner loop, yet still control from the controller set up to the middle loop... when I expected naively perhaps, to have to change to the inner loop controller.

In addition to this... I'd like to know how to simply wire ancient Hornby electric points. I have a couple of these to hand, and tried applying power from two flying leads, which issue from the side of the duette and convey what is described as 12 Volts unregulated I think. Using one as a common on the middle terminal I was able to make the points switch by applying the other to either one of the others.

I do not know electronics... believe me I wish I did... I spent my time at uni doing something which is now relatively ubiquitous... they called it computing... but I can solder and I can work out simple circuits... although not diagrams.

Here we are, as far as we've got, in one of the attics...







Regards

dublover

QUOTE (Gary @ 21 Oct 2006, 10:01) <{POST_SNAPBACK}>The airbrush topic was and is very interesting.

What questions do you have on Dublo 3 rail?

It will work with Marklin 3 rail and you can run Marklin stuff on Dublo and vice versa. I have done this myself. As both systems were developed before the war I guess Meccano deliberately designed their track to be compatible with Marklin in the hope that the Germans would buy Hornby Dublo as a low cost alternative to Marklin.

Happy modelling
Gary

The isolating points were introduced in 1953. Points produced before then were not.

You need to pick up some Dublo insulating tabs to isolate the middle rail and create breaks in appropriate places. Slip it in between the tongues as you join the track.

And you need the short isolating track pieces to create isolated sections.

Hornby Dublo offered all this and the wiring of Dublo can be a complex area if you create complex layouts! Thats why Dublo on/off Lever Switches and the accessories mentioned above are in such great demand and fetch massive prices on eBay!

The old Dublo track plans included symbols for both the positioning of insulating tabs and short isolating track pieces.

Best to design a layout using these accessories as appropriate when you are incorporating the older live points rather than start altering the points.

That is a fantastic set up you have there. I do like the Hornby Dublo kit as it was built to last forever and is good solid British engineering!

Happy modelling
Gary

You need to indicate where on your layout you have the electrically live points fitted.

Nobody can really help you with specific placement until you provide this information.

It is in reality going to be much easier to simply purchase more isolated points than to start attempting to alter older live points. You can see exactly from the images you have provided why this task is almost impossible!

You are almost certainly going to need to put some breaks in where one oval joins to another else you will get shorts unless you turn the power off on one of the ovals.

Happy modelling
Gary

>I do not know electronics... believe me I wish I did...

Forget the electronics - you don't need to know anything about them in this context.

>and I can work out simple circuits
That's all you need to do here.

>I spent my time at uni doing something which is now relatively ubiquitous... they called it computing... but I can solder

OK. Here's a suggestion to see if we can translate this electrical problem to the computing domain you are familiar with.

Each point has 3 connections in and 2 sets of 3 connections out. Lets call them RailA, RailB and RailC where RailC is the centre rail.

You have two types of point which have two different types of truth table. I can't see the connections for the two outside rails, so I don't have enough information to create the truth table for RailA and RailB but if I get the idea across, you can do that for yourself. I believe in the context of 3 rail it doesn't really matter since they carry the same polarity - is this correct??

The truth table for the permanently live points (That's the two on the left of your photo) is as follows:-

Straight ahead: RailC (StraightAhead) = RailC (In); Rail C (Turnout) = RailC(in)
Turn out: RailC (StraightAhead) = RailC (In); Rail C (Turnout) = RailC(in)

The truth table for the isolating points (That's the three on the right of your photo) is as follows:-

Straight ahead: RailC (StraightAhead) = RailC (In); Rail C(Turnout) = OFF, Nothing, Niet, Rien, Nada
Turn out: RailC (StraightAhead) = OFF ; Rail C(Turnout) = RailC (In)

Now pick a location on your middle loop and build a tree of the connections from that location. Each time you encounter a point, introduce a branch. Depending on the type of point used, apply the appropriate truth table. Once you have built the tree, you can work out what rails are powered for each combination of settings.

Having written all this out, I think you can make your layout work if you ensure that all your crossings have at least one isolating point in them. So that's locations (1,2); (2,3); (5,3); (4,1). Co-ordinates are x,y and reference the origin of the containing square.

>I had hoped for more than that from this forum.
I don't know what forums you used to, but here it can take a few days for people who feel confident to answer coming across your post and making a suggestion. This is a fairly quiet forum but I think it has a good signal to noise ratio compared with other busier ones.

Let us know if it works.

David

Thanks for this, I'm going to go and try out the final part ASAP.
However, I must point out that tt was not even apparent to me that the RHS points in the pics were the isolating ones.

You're quite correct to chide me for impatience, and I stand so... chided. The forums I do frequent as a rule are probably far too quick to return answers... but then you seem to know what computer folk are like so I think it must also be apparent to you.

I do admire the truth table approach. It is so long since I saw that... I'll bet you remember CP/M too... and the great old Z80 processors. I prefer the last bit though.

I confess to forgetting entirely about some little pieces of paper which fell out of the points boxes... these would be the insulators mentioned, and I do recall... now that you and Gary have stimulated the neurons... reading somewhere that they were to be employed in a fashion as described. I discounted them I think since I was using some self-adhesive green baize for the base... and it is of course electrically inert... but then of course so is a wooden board.

I have decided to approach the business along the lines you detail... for which I thank you for your advice.

I will firstly isolate the inner loop from the middle... which is where the problem is most apparent. I actually isolated the sidings at 1,2 by removing the very short straight into that area as it was a sort of minor issue for the time being and better back burnered for now.
I think a run at 5,2 is the first step. Then if that returns some positives, perhaps the other cardinal... as you identified... in that area at 2,3

Bear with me however. I'm no longer nimble and it may take a day or so.
I do have now three locos which seem eminently capable of returning the results... if there are any. One of the others turned out to be a bit on the jaundiced side itself and tended to indicate faults by it's own intertia. At one stage it even smoked... something I've not been allowed to do for years now.

Both of the problem locos came from a bod on eBay. To be fair though, only one of them was priced at a level where you might expect to get a reasonable runner I apprehend. And I have not taken the matter up with him, preferring instead to wait and have them completely serviced by a chap who is currently on holiday.

So with two fully functional Duchesses... Athol and Montrose... and a little green 0-6-2 to work with, I may yet resolve this with your help.
One thing I seem to recall finding most disconcerting was that the isolating points registered current every which way, no matter which way I set them. On reflection of course that has to be the fact that even if you remove power from one loop, the power from the other is still naturally present.

dublover... currently ascending mount attic, to change some points.

QUOTE (dwb @ 21 Oct 2006, 12:44) <{POST_SNAPBACK}>>I do not know electronics... believe me I wish I did...

Forget the electronics - you don't need to know anything about them in this context.

>and I can work out simple circuits
That's all you need to do here.

>I spent my time at uni doing something which is now relatively ubiquitous... they called it computing... but I can solder

OK. Here's a suggestion to see if we can translate this electrical problem to the computing domain you are familiar with.

Each point has 3 connections in and 2 sets of 3 connections out. Lets call them RailA, RailB and RailC where RailC is the centre rail.

You have two types of point which have two different types of truth table. I can't see the connections for the two outside rails, so I don't have enough information to create the truth table for RailA and RailB but if I get the idea across, you can do that for yourself. I believe in the context of 3 rail it doesn't really matter since they carry the same polarity - is this correct??

The truth table for the permanently live points (That's the two on the left of your photo) is as follows:-

Straight ahead: RailC (StraightAhead) = RailC (In); Rail C (Turnout) = RailC(in)
Turn out: RailC (StraightAhead) = RailC (In); Rail C (Turnout) = RailC(in)

The truth table for the isolating points (That's the three on the right of your photo) is as follows:-

Straight ahead: RailC (StraightAhead) = RailC (In); Rail C(Turnout) = OFF, Nothing, Niet, Rien, Nada
Turn out: RailC (StraightAhead) = OFF ; Rail C(Turnout) = RailC (In)

Now pick a location on your middle loop and build a tree of the connections from that location. Each time you encounter a point, introduce a branch. Depending on the type of point used, apply the appropriate truth table. Once you have built the tree, you can work out what rails are powered for each combination of settings.

Having written all this out, I think you can make your layout work if you ensure that all your crossings have at least one isolating point in them. So that's locations (1,2); (2,3); (5,3); (4,1). Co-ordinates are x,y and reference the origin of the containing square.
>I had hoped for more than that from this forum.
I don't know what forums you used to, but here it can take a few days for people who feel confident to answer coming across your post and making a suggestion. This is a fairly quiet forum but I think it has a good signal to noise ratio compared with other busier ones.

Let us know if it works.

David

Back from Mount Attic... it's always very warm up there.

Your Mum must have fed you on good grub when you were young David... it worked very well.
I have to re-align a rail or two, but the idea is there. Thank you very much indeed.

The transfer from inner loop to outer worked... at least as far as I expected it to... you were right, the points installed were not the right hand variety (in the photo) but the left... shorter connection type, for the most part.

Mind you, if I'd been pushed and had no alternate to try, I reckon you could convert from one type to the other without too much problem. It's really only a matter of establishing those solder islands. The physical aspect of the point is precisely the same.

LMK if you want to go back to Z80. I have some Memotech Computers here. We used them for teaching Z80 as they have a built-in Assembler and a Front Panel for testing code. I even found a Z80 development system that I worked with, in the pile. Popped it on the new auction site we're using instead of eBay now.

http://www.specialistauctions.com/auctiond...s.php?id=190433

I'll change the other points at 2,4 tomorrow perhaps. I couldn't wait to try out your idea so I managed to get up there this afternoon.

Thank you most sincerely once again.

dublover

QUOTE (dwb @ 21 Oct 2006, 15:42) <{POST_SNAPBACK}>>I'll bet you remember CP/M too... and the great old Z80 processors
I've been rumbled! I did some interesting things with CP/M and a lot of Z80 programming in assembler....

I wish you luck in the attic; going back up there myself now - more track to lay.

David

I was a bit baffled as to the real reasons why the 68000 died away. I know it had a run in Macs and Atari STs and all, but how that... thing... (the 8088 and 8086 die) which was designed to control a piece of a chemical plant and had such severe memory limitations hard-wired in survived to power all PCs I'll never know. It's typical human perversity... VHS and Betamax, and for all we know Blue-Ray and HD DVD.

If you still program at all then I lift my titfa to you.
The last programming I did was forced work, I looked around for the easiest way and stopped at a thing called Liberty Basic.
It allowed me to create an app in Windoze, with associated dlls if necessary (what we used to call an external library of functions someone else had already made I think... or cheating using someone elses work, for the purists). I reckon those boys who knocked up that XTrkCAD might have used something similar.
Anyway... I had it to do for a PC to PDA app. Clever things those PDAs, especially the older HP Jornada 720s.
And for once Microshaft actually did the users a favour in producing an APP for them, called ActiveSync... and for free!!
If you use one (PDA) you'll know what I mean. If you don't, then good for you... you've managed to avoid them. They're the next stage of PCs I think... along with the dichotomous shift into the living room and integration of the pc/internet with the TV-Video-MP3 system. The modern PDAs, like our XDAiiS units, really need a virtual screen... amazingly someone already did the virtual keyboard... and that'll more or less do it.
I've lost count of the programs around now for converting DIVX movies to PDA. Someone must be buying them.

Anyway, all that aside, I will endeavour to ascend those killer stairs again today and replace the other points with isolating point spares, which I hope are in that mess of sidings on the left... otherwise it's back to eBay for some more. )

I can't tell you how much this bulletin board and you have helped me this week, and I obviously can't repay you any tangible way.
What I can do is to share with you the best laugh I've had in a long time, which came in this week's night emails.

A little old lady from Kansas had worked in and around her family dairy
farms since she was old enough to walk, with hours of hard work and
little compensation. When canned Carnation Milk became available in
grocery stores in approximately the 1940's, she read an advertisement
offering $5,000 for the best slogan. The producers wanted a rhyme
beginning with "Carnation Milk is best of all...."

She thought to herself, I know all about milk and dairy farms... I can
do this!
She sent in her entry, and about a week later, a black limo drove up in
front of her house.. a man got out and said, "Carnation LOVED your entry
so much, we are here to award you $1000, even though we will not be able
to use it..."

Here is her entry:



QUOTE (dwb @ 21 Oct 2006, 22:11) <{POST_SNAPBACK}>>Your Mum must have fed you on good grub when you were young David... it worked very well.
Excellent news!

>if you want to go back to Z80
I have tasted the fruits of ARM 9. I have no desire to go back though I am sad the Nat Semi 32000 never took off. It's mostly C++ for me these days.

David