Jump to content
 

DC layout wiring - HELP!


Recommended Posts

I have wired my layout as per the attached diagram. All the positive feeds are one side of the track (ie. North rail sides looking at diagram) with in-line switches for the sectional power feeds. The other sides of the track is wired to a common negative feed (South rail sides looking at diagram) and not switched. When controlled power is fed to the layout, I get a short on the controller which operates the internal cut out. I have checked all wiring and there are no crossed wires. However, putting a circuit tester on the power switches shows a complete circuit (lights the bulb on the tester) irespective as to whether the switch is on or off - this happens with all switches apart from number 1. I can also put the tester on the track with one probe on the positive side and the other probe on the negative side of the track, and the tester bulb lights up in every case.

 

I am at my wits end trying to understand what's going on and why there is a short somewhere. Somewhere positive is being connected to negative on a permanent basis, but I've not a clue where it is. Please help!!

IMG_20190616_221808.jpg

Link to post
Share on other sites

  • RMweb Gold

Too many feeds and not enough breaks. Look upon it in the sense that power should only enter a point from the toe end. You will need a break between feeds 5 and 6, between 4 and 7, between 5 and 3 and between 2 and 5.

Edited by Mick Bonwick
  • Agree 1
Link to post
Share on other sites

It looks like you are using live frog points (Electrofrog if Peco). This means that the points themselves are causing the short circuits not your wiring. You need to add more rail breaks or have less track feeds.

 

BTW Feed number 1 is the ONLY properly isolated feed on the whole diagram.

 

BTW if you need more help you need to let us know what kind of points you are using.

 

Regards,

 

John P

  • Agree 2
Link to post
Share on other sites

The whole lot will short out if you use live frog points.  Even with the positive section switches switched off  the negative non switched feeds will feed the frog end of the points and short out and there are no combinations of point settings which will allow the trains to run.  Quick cure.   Cut the feed wires to 2/3/5/7/4 on the negative non switch side and switch the other side off.

You only need 1/6/8 feeds for DC. 

I think you have been swept up in the DCC put feeds absolutely everywhere philosophy without embracing the need for isolators just about everywhere philosophy.  For DCC put double isolators on the frog end of the points and spend weeks attaching droppers to every bit of track instead of doing any modelling.

Link to post
Share on other sites

  • RMweb Premium
5 hours ago, DavidCBroad said:

The whole lot will short out if you use live frog points.  Even with the positive section switches switched off  the negative non switched feeds will feed the frog end of the points and short out and there are no combinations of point settings which will allow the trains to run.  Quick cure.   Cut the feed wires to 2/3/5/7/4 on the negative non switch side and switch the other side off.

You only need 1/6/8 feeds for DC. 

I think you have been swept up in the DCC put feeds absolutely everywhere philosophy without embracing the need for isolators just about everywhere philosophy.  For DCC put double isolators on the frog end of the points and spend weeks attaching droppers to every bit of track instead of doing any modelling.

Why would it take weeks to put droppers in?

 

But the layout is for DC anyway, so almost everything you said is irrelevant.

  • Agree 1
Link to post
Share on other sites

1 hour ago, kevinlms said:

Why would it take weeks to put droppers in?

 

But the layout is for DC anyway, so almost everything you said is irrelevant.

Because it has taken me months to fit droppers to our outside branch.  I only decided to add them as the outside branch approaches 10 years old and failed fishplates and broken link wires have become a regular occurrence.  Drilling holes for droppers and soldering is very tedious and boring and with my standard of soldering looks ugly or falls off at the first sign or frost

The jury is out on whether the droppers will actually help as the bus wiring has to have quick detach connectors to allow the lift out section to be removed for access to one side of the shed and making them weather proof is a challenge.

 

Please explain why my advice is wrong.  I wrote

 

The whole lot will short out if you use live frog points.  Even with the positive section switches switched off  the negative non switched feeds will feed the frog end of the points and short out and there are no combinations of point settings which will allow the trains to run.  Quick cure.   Cut the feed wires to 2/3/5/7/4 on the negative non switch side and switch the other side off.

 

See diagrams below, You only need 3 feeds (1/6/8) for DC. 

On the other hand you need 17 feeds for full DCC wiring, and 18 sets of double isolators adding which  means taking up most of the track244260744_Screenshot(392)DCC.png.05c60a9b0a749e5592a65de72c884056.png

Screenshot (392)DC.png

Edited by DavidCBroad
Link to post
Share on other sites

  • RMweb Premium
5 minutes ago, DavidCBroad said:

Because it has taken me months to fit droppers to our outside branch.  I only decided to add them as the outside branch approaches 10 years old and failed fishplates and broken link wires have become a regular occurrence.  Drilling holes for droppers and soldering is very tedious and boring and with my standard of soldering looks ugly or falls off at the first sign or frost

The jury is out on whether the droppers will actually help as the bus wiring has to have quick detach connectors to allow the lift out section to be removed for access to one side of the shed and making them weather proof is a challenge.

 

Please explain why my advice is wrong.  I wrote

 

The whole lot will short out if you use live frog points.  Even with the positive section switches switched off  the negative non switched feeds will feed the frog end of the points and short out and there are no combinations of point settings which will allow the trains to run.  Quick cure.   Cut the feed wires to 2/3/5/7/4 on the negative non switch side and switch the other side off.

You only need 1/6/8 feeds for DC. 

You also wrote this, which is wrong. Why bring DCC into a discussion on DC wiring. It only confuses people with little experience.

 

"I think you have been swept up in the DCC put feeds absolutely everywhere philosophy without embracing the need for isolators just about everywhere philosophy. "

 

I've not built an outdoor layout, but from what I did read, much of your problems with your outdoor layout, is because of your poor soldering. Not sure of the difficulty. Plenty of advice to be found on soldering, within RMweb.

Link to post
Share on other sites

  • RMweb Premium

I think the answer is somewhere between the original schematic and the stripped back bare version posted by David.

Personally I would want some more versatility for the trackwork at bottom left as with the minimum suggested it is restricted to one movement at a time over the whole area.

 

  • Agree 2
Link to post
Share on other sites

  • RMweb Premium
2 hours ago, DavidCBroad said:

Because it has taken me months to fit droppers to our outside branch.  I only decided to add them as the outside branch approaches 10 years old and failed fishplates and broken link wires have become a regular occurrence.  Drilling holes for droppers and soldering is very tedious and boring and with my standard of soldering looks ugly or falls off at the first sign or frost

The jury is out on whether the droppers will actually help as the bus wiring has to have quick detach connectors to allow the lift out section to be removed for access to one side of the shed and making them weather proof is a challenge.

 

Relying on fishplates for an outside layout was IMHO wrong in the first place.

A soldered joint will not fail under frosty conditions. A  "dry" joint where the the materials havent bonded due to incorrect soldering conditions will.

There are available weatherproof exterior connectors which could be used to enable sections to be unplugged. If you want quality dont think cheap.

  • Agree 2
Link to post
Share on other sites

Assuming you have Electrofrog points, consider how they work. 

 

The point blades connect the frog to the stock-rail they're touching - as a result they will short the route not selected by the point if you've not put in isolators.  If you've put the feed on the toe end of a turnout into a couple of sidings this is fine - you'll just get the same polarity on both rails so nothing will move on the track not selected - for example, lose feed 4 and you don't have to do any work to the turnout to the left of feed 7. Where you've got crossovers, etc. on a running line you'll need extra isolators. 

 

Consider, for example, the turnout two to the left of feed 5, switch it to the straight road and feed 2 will short out, switch it to the lower road and feed 3 will be shorted out. For the same reason you will also have trouble with shorting on feed 7 depending on how the point to the right is set, feed 4, depending on how the point to the left of feed 7 is set, and probably some other combinations I've missed. 

 

As Melmerby was alluding to, I'd be tempted to put in isolators just south of the turnout to the left of feed 5, and add a feed in to the sidings at that point so you can do shunting operations independently of what's happening on the main line. 

 

Link to post
Share on other sites

David Broad made this comment

 

On the other hand you need 17 feeds for full DCC wiring, and 18 sets of double isolators adding which  means taking up most of the track

 

Don't have to take up track to put isolators in - a dremel type cutting disc will do the trick and one can put them where they like then glue some thin styrene in the cut, trim & once painted the same as the rail, won't be noticed.

  • Like 2
Link to post
Share on other sites

Just for clarity here is the wiring shown back to a single controller.   This is common return.  You can run each feed and return through a double pole switch if you prefer.  There is a danger that the loco in the platform can be driven into the heel of an incorrectly set point and short it out. Not a huge problem as long as the loco does not have plunger pickups like the Airfix 0-4-2T. If it does then the short will destroy the pickup springs.  I speak from experience.

If the plan is for Insulfrog points then the isolators can be removed completely and one feed becomes unnecessary as well. (see pic)

I might be advisable to add isolated sections.    Top tip, Always run isolator wires from one side of the break back to a switch and back to the other side.  If you just add a one sided feed and stop a wagon across the break you can short out the layout and cause much head scratching.  The wagon never makes contact immediately, but give it an hour or so.  I have lost count of the times a metal wheel across an isolator from a feed has stopped our layout

Also the isolated break can be green or blue side of the wiring.     

Screenshot (392)DCa.png

 

Screenshot (392)DCb.png

Edited by DavidCBroad
Link to post
Share on other sites

Guys, many thanks for all your helpful replies, and apologies for not getting back to you sooner. I am in Germany at the moment with very bad internet connection, and will look at the best solution at the weekend when I’m back home. As my switches are already mounted, I would prefer cutting rails than destroying the aesthetics of the control panel. Any chance in the meantime of someone doing me a diagram with marks exactly where I need to do the rail breaks please? I also have a three road fiddle yard at the bottom right of the layout with two points, so please take this into consideration. All help greatly appreciated. 

Link to post
Share on other sites

You don't need to change anything except permanently turn off all but the three switches in David's top diagram! :-)

 

As to the fiddle yard, we'd need a little more detail on how it's laid out/how you intend to operate it. 

 

Assuming that, as you come from the station, the two points are 'facing' the direction of travel so the train can run directly into each siding, and assuming that you're just going to uncouple the loco, pick it up and put it back on the other end of the train, rather than couple another loco on the back and drive the train out, then precisely no further wiring is required whatsoever!

 

Link to post
Share on other sites

37 minutes ago, DavidCBroad said:

Screenshot (401)a.png

Screenshot (401)b.png

Thanks for the update David. I have two options it seems - I favour making more isolations in the track, which will give me more versatility to say do some shunting in the yard while I have a loco/train in the station - would you agree.? It would also save me destroying my switch panel! The fiddle yard (just beyond feed '8') is just two points so that the train can run straight into each siding. Can you confirm what RJS1977 has said, that I won't need any further wiring or rail cuts for this please?

 

Incidentally, the layout is in 3mm using Peco live frog HOm track. The track plan is of Spilsby in Lincolnshire (closed in 1933) with an added head shunt.

Thanks

Martin

 

Link to post
Share on other sites

See my bottom sketch above. It gives some isolators at siding/ platform ends for holding locos and keeps all the switches

The white feed at 4 has to go or the layout wont run unless the points are set for no 4 siding.

The head shunt is not really in the right place, if it was as per my drawing a train could arrive or depart while another shunts.

The original station like the majority of small terminus stations didn't have a headshunt and the main line was used for shunting. Very safe as the loco was at the country end of the movements and no other train was allowed into section. Quite often a small loco would pull a huge raft of wagons out of the sidings before sorting them into those to remain and those to go and then put them in the right sidings.  I like doing that on our outside BLT as it has 50 feet of main line to shunt along

Headshunts were more common where the tracks dipped down steeply from the terminus, Princetown GWR being one though  a lot of stations still didn't have them, the GWR liked short headshunt like spurs as a wagon hitting the buffers was not guaranteed to derail whereas one running through a catch point on to the ballast was guaranteed to, which meant sending for the breakdown gang and causing maximum disruption 

Link to post
Share on other sites

On 22/06/2019 at 12:54, DavidCBroad said:

See my bottom sketch above. It gives some isolators at siding/ platform ends for holding locos and keeps all the switches

The white feed at 4 has to go or the layout wont run unless the points are set for no 4 siding.

The head shunt is not really in the right place, if it was as per my drawing a train could arrive or depart while another shunts.

The original station like the majority of small terminus stations didn't have a headshunt and the main line was used for shunting. Very safe as the loco was at the country end of the movements and no other train was allowed into section. Quite often a small loco would pull a huge raft of wagons out of the sidings before sorting them into those to remain and those to go and then put them in the right sidings.  I like doing that on our outside BLT as it has 50 feet of main line to shunt along

Headshunts were more common where the tracks dipped down steeply from the terminus, Princetown GWR being one though  a lot of stations still didn't have them, the GWR liked short headshunt like spurs as a wagon hitting the buffers was not guaranteed to derail whereas one running through a catch point on to the ballast was guaranteed to, which meant sending for the breakdown gang and causing maximum disruption 

Hi David

I have opted for option two (your second solution above), which now works. However, I am still getting a short at feed 8 for some reason, with and without the fiddle yard connected (its on a different board). Any ideas please? Regards, Martin.

Link to post
Share on other sites

4 minutes ago, Emmo said:

Hi David

I have opted for option two (your second solution above), which now works. However, I am still getting a short at feed 8 for some reason, with and without the fiddle yard connected (its on a different board). Any ideas please? Regards, Martin.

Ignore my last - just found the problem. I have mounted the connector plugs for the fiddle yard board on one piece of double sided PCB board, with copper on both sides!! Duh....!

  • Friendly/supportive 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...