Polarity Problems

A

adamski

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Evening all

Hope you're all keeping safe in these peculiar times. Whilst I've had a bit of spare time on my hands, I thought I'd spend it making a few adjustments to my layout, probably should have left it well alone because I've managed to muck it up and have a devastated 3 year old and a grumpy Mrs on my hands with no prospect of escape anytime soon!

I've attached photos and a drawing of what I currently have, I'm running Massoth DCC, but have basically somehow managed to overlook the fact that the polarity on the inner and outer loop are different at the section to which I have attempted to install a crossover and set of points to allow swapping locos from the inner to outer loop etc. I can't swap the polarity over on one of them because elsewhere, as per the pics, the tracks are linked and the polarity is correct there.

Any ideas anyone please? I have a spare massoth reverse loop module if that might do something? I'm pretty desperate to get it fixed so we can spend the day playing tomorrow!

Thanks

Adam
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OK, so the crossover switch is a double slip switch.

So what was added that caused the problem? I see 2 switches that make a "crossover" in the foreground, and the double slip further away.

So, please clarify what the configuration was when it worked, and what was added/changed.

Greg
 
Hi Greg

So, where the double slip is now, which I added today, used to be just a standard crossover and worked fine. The 2 x R3 points which you can see in the photograph were also added today and are causing a short - if you zoom in on the second photo, I have marked the polarity on the tracks.

Before the double slip and 2 x R3 points were added, it all worked perfectly, but we need the ability to switch locos from inner to outer loop at this point

Cheers

Adam
 
Ahh... you calling a crossover is called a "crossing" or "diamond"...

OK, we have to agree on the terminology.... I will use the terminology I have stated.

So, not sure on how the LGB double slip works in terms of connecting but let me give you my best advice, which means the fastest way to your solution.

1. remove the double slip switch and put the crossing back in.
2. now you need to solve the issue caused by causing a "reverse loop", which is used kind of generically, when you wind up connecting the left rail to the right rail in some configuration. This will require an autoreverser.
3. you need to insulate the "reversing loop section" and feed it with an autoreverser.
4. right now, you need a break in the outer/left track (referencing last picture) BEFORE the switch.
5 the next question is where to put the other insulator, with the crossing in place, just before the crossing will work, but you might have to move it later BECAUSE #6
6. not sure how the double slip is wired, might have to move the insulator WHEN you try to put that back in.

I'm suggesting a step by step procedure so a failure at any point can be debugged remotely.

Making both changes at the same time should really increase the difficulty.

Greg
 
Hi Greg

Thanks for the ideas. Please see two attached drawings, one of the existing layout with diamond crossing and one of what I'm trying to achieve.

If I were to install the massoth reverse loop module, where would you recommend I install the insulated sensor track sections? I also had a thought - what would happen to the polarity if two trains crossed the insulated sensor track sections simultaneously or within a short timeframe? The second loco crossing the section would short it out?

Thanks
Adam

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AS I understand the situation you had 2 independent lops with different polarity and you now want the lops to interchange. Why did you chose to have different polarity ? Would it not be a simple solution to change the inner lop polarity to match the outer lop ?
 
I don't think the double slip is the problem.

I think the problem is at the top of the first sketch in post #1 where it says 'Outside Loop' and there are two sets of points to the Inner Loop.

If you follow the route of the Inner Loop, you'll find that it is a figure-of-eight, so by the time it gets to that position in the garden, polarity is reversed.

Well, I could be wrong, but that's what I think ............. at the moment ................. :think::think::think:
 
Alexander0654 said:
AS I understand the situation you had 2 independent lops with different polarity and you now want the lops to interchange. Why did you chose to have different polarity ? Would it not be a simple solution to change the inner lop polarity to match the outer lop ?
Click to expand...
First, I don't see a reversing loop.

If you have a short at the interchange between the 2 tracks, then it is because you are running the 2 loops at different polarity. Maybe you have them that way because the trains run in opposite directions?

Are both loops fed from the same power pack, or from 2 different ones?

There is a crossover shown at the top (opposite end of the layout from your new problem area.) Why don't you get a short circuit there? Do you have insulation between the 2 loops on those crossovers?

Basically, you need to isolate both loops so you can safely run 2 trains at once, which means insulation at the crossover and at the double-slip. (I suspect the latter already has insulation as it doesn't cause shorts.)
Edit: looking at your diagram of the double-slip, it doesn't have insulation between the two crossing tracks, so you can't use it if you intend the 2 loops to be independent.
 
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I'm wondering why you have a double slip and a crossover so close together, as you don't need both?

The double slip effectively combines a diamond crossing with a crossover, so you are adding unnecessary complications which doesn't look prototypical.

I would revert back to your original plan and then add either one or the other, but if you are using the slip in a reversing loop instead of the diamond, then that the root of your problem....
 
Looking again at your track plan, you have an inside figure 8 loop and an outside loop. These are linked by cross overs at the top of your diagram.

The fig 8 reverses the polarity, so you need to fit a Massoth Reverser in both sides of your inner loop to use your DS, from either side of the afore mentioned crossovers, to just before the DS....
 
Gizzy said:
The fig 8 reverses the polarity, so you need to fit a Massoth Reverser in both sides of your inner loop to use your DS, from either side of the afore mentioned crossovers, to just before the DS....
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Gizzy, I don't see why the figure 8 reverses the polarity. It isn't even a crossing - there's a fly-over bridge. A train going into that inner loop comes out pointing the same way and going in the same direction.
 
Fred, see my post #10

The figure of 8 is not a problem until the two pairs of crossover points are installed at the top of the diagram - at that point in the track arrangement, trains will be going in different directions on either loop ...................

...... I think :think::think:
 
Fred2179G said:
Gizzy, I don't see why the figure 8 reverses the polarity. It isn't even a crossing - there's a fly-over bridge. A train going into that inner loop comes out pointing the same way and going in the same direction.
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It's because there is crossover at the other end of the for 8, top of Adam's diagram Fred....
 
Gizzy said:
It's because there is crossover at the other end of the for 8, top of Adam's diagram Fred....
Click to expand...
You lost me. Clearly if the outer loop is set to run the opposite direction from the inner loop, then there's a problem at those crossovers. But they don't reverse polarity by themselves. If there is only 1 power pack, then there won't be any polarity problem as there is no reversing loop.
 
Fred2179G said:
You lost me. Clearly if the outer loop is set to run the opposite direction from the inner loop, then there's a problem at those crossovers. But they don't reverse polarity by themselves. If there is only 1 power pack, then there won't be any polarity problem as there is no reversing loop.
Click to expand...

All I can say Fred, is that there was no short circuit with the diamond crossing.

As soon as the Double Slip was installed there is a short.

I have a DS myself with a return loop and I was very careful how I used it with my Massoth DCC system. I have the LGB DCC reversing units to solve this issue.

We will have to agree to disagree....
 
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