Crossing short

[wildebeest]

Hi all. I have a short I've not been able to solve thus far and am hoping someone on here can give me a steer in the right direction Here's the background, which I hope will also be clearer from the attached sketch of my branch/dock junction. It is a DC layout with copper clad points; x2 Gaugemasters in use with no cab control wired in as yet; mixture of Cobalt Analogue and Seep (with polarity switching) point motors, all of which working okay independently. This issue is with the central point 2, which gives access from the branch to the top dockyard siding. When switched to the dock, it is ok but when switched back to allow transit across the branch, it shorts out. I hope the frog wiring set-up is clear on the diagram but basically Point 1 controls polarity switching of frogs A, E and G; Point 2 controls frogs B and D and point 3 controls frogs C and F. I have but the barest grasp of all things electric, so I will probably have to come back for further clarity on any responses you are kind enough to offer........just setting some expectations Thanks in advance.

[Bigmet]

Is the section between point 2 and point 1 isolated from supply when point 2 is set for the dock siding? If so first suspect to check out is one sleeper not fully gapped on point 2 or in the track to point 1. A strong light like an LED torch grazing across the top of the sleepers is where I would start, just in case there is stray piece of copper across a gap. (Been there, got that T-shirt...)

[Bufferstop]

You don't mention it, do your copper clad points 2&3 have insulated joiners or insulating gaps on the V rails of the frog? If not they will be applying a short circuit to the unselected road. It would help to know where the power feed is in relation to this junction, and is it part of a continuous loop.

[pete12345]

Regarding isolation gaps, from what I can see you need the following:
- Blue rail between 1 and 2
- Black rail between 1 and 4
- Both rails between 2 and 4
- Both rails between 4 and 5
- Both rails between 3 and 5

You will also need gaps at all four rails inside each diamond crossing, and between each point frog and the blades.

For completeness with the additional trackwork:
- Black rail on the line right of 5
- Black rail on the line beneath 5
- Black rail on the line beneath 4

Some of these may be included as part of the section breaks, where presumably you're isolating both rails anyway.


If all of the above are in place, I can only suggest is must be a sleeper not properly gapped, or some solder gone astray and bridging a gap somewhere.

[wildebeest]

Thank you for your responses. I shall be braving the chill to head out to the railway room this evening and try/check all your suggestions.

[Bigmet]

Best of luck with it! Patience will get you there.

[Mountain]

The way I go about it is to build the track first and then using a minidrill and a carbodium cutting disc (Use eye protection), make cuts where required, and I then put playdough around each cut in the rail and poured in a resin mix from a casting kit.

Of course one can use glue or something else... Resin seemed the most appropiate insulator at the time.

[wildebeest]

Hmmmmm.....something has changed by checking all of those isolation points, as the original short no longer occurs. Instead, I have lost power over frog 2. At 23:15 I conceded defeat and came into the warm!

I've used a lot of 'Wago' connectors as they make the initial wiring so easy to change if you get it wrong ( I really am excellent at that part). I'm tempted to go back to the start and re-wire the entire section, a stage at a time, testing as I go. I've spent so many hours trying to fix this junction on the fly, it has removed all joy from the hobby. I shall report back with either a success or a 'layout for sale' message

[Bigmet]

....something has changed by checking all of those isolation points, as the original short no longer occurs. Instead, I have lost power over frog 2...

Potentially good news. The short has gone away when frog 2 isn't powered. That suggests that it is the isolation of that frog from the rails leading to point 1 where the problem arises.

[wildebeest]

Hi all. 4 hours in the shed last night......brrr. No further forward despite much experimenting. Another variable came into question last night? Point 1 is a Cobalt, points 2 and 3 are Seeps. We are noticing a high voltage in certain switched positions on frog 2. Is anyone aware of any incompatibilities between combining Cobalt iP Analogue and Seep motors on the same layout?

[Bigmet]

There's no incompatibility between different types of point motor, each is a stand alone unit in respect of its functions.

The problem you are describing has wiring and/or point motor railswitch connections and/or rail connection(s) and isolation written all over it as the cause. Sorry to be brutal, but you may do best to follow what you suggested earlier:

...I'm tempted to go back to the start and re-wire the entire section, a stage at a time, testing as I go...

[wildebeest]

Good to get that confirmation Bigmet, thanks. It presented itself as a possible shortcut/alternative fix, rather than going back to the start......