# Some questions about DCC track wiring from a newbie



## Darrkon (2 mo ago)

Hi all,
I am new to the forums and model railroading and in the process of building my first proper layout. I was going to stick with DC using two controllers (one for an inner loop and one for an outer loop) with the loops joined by turnouts that were insulated from each other. But I couldn't picture how a train would move from one loop to the other and decided to go to DCC.

The layout is basically a big loop. Inside the big loop is a smaller loop with one set of turnouts to join them together. Outside of the big loop will be a small siding connected to the big loop by turnouts - this will be a little 'yard' type area for small trains and carriages to move around. The turnouts will be PECO insulfrog but I was NOT planning to use any insulated joiners between them (unless someone says I should).

The entire layout board is 120 x 180cm (or 6 x 4) and if I run one set of wires from the controller to the track, I can run a couple of trains reasonably well (though at some points the trains seem a little jerky in their movements). I put the jerkiness down to some track pieces being very old with poor fitting fish plates and potentially needing to use bus wiring to more points on the rails. It could also be the decoders or the controller I guess - those are just basic Hornby 4 pin decoders a Hornby Select controller.

I am planning to replace most of the big loop with flexi track - this will reduce the number of joins/old rail. But the questions I have are:

Do I need bus wiring for a layout of this size? (I suspect this is a yes)
If I do implement bus wiring, do I need to break each of the rail loops with a set of insulated joiners (I could not find a clear answer on this) I understand the bus wire itself does NOT make a loop, but the rails will make a loop.
What would be the suggested number of drops for a layout of this size? I see some people say one per track piece, others say every 1m/3ft.. I am thinking 5 or 6 - two per loop and two for the yard area
Thanks in advance for any/all input with this!

Cheers!


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## REdington (Aug 20, 2018)

Yes, you will still need a buss of some sort. The general rule of thumb is each piece of track needs feeders attached. The resistance of the rail is the reason why DCC need all those feeders.

Another thing is when using flex track in curves, you need to solder the 2 pieces together while the joint is straight. If you don't, you have a great chance of getting a kink at the joint,


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## DonR (Oct 18, 2012)

You have a very simple wiring situation. From your description of
the track plan there is no need for any insulated joiners. All
track sections should be connected by tight metal joiners. Most
of us will provide a drop from the track to the DCC bus every
6 feet or so. You mention older track. The rails should be 
cleaned and clear of any corrosion. For smooth train running
you must have clean track and clean loco wheels.

You are wise to have chosen Peco Insulfrog turnouts. They
are quality products and you will have many hours of
derail free operations. You should know that Insulfrogs
are power routing. That means that a divert track will
go dead when the points are set to straight. Make sure
you have a drop to bus from any stub track that you
wish to always have power.

Which ever DCC control system you select will power
3, 4 and even more trains running at the same time,
and you'll have individual control of each. Have fun
with your new layout.

Don


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## OilValleyRy (Oct 3, 2021)

As to feeders/bus:
I would mount a small terminal strip underneath at each end in the 6ft direction. Have your bus go from DCC base station to one, then to the other. Feeders can tap off of the terminal strips to the loops from there, either in the half-way point through the curve, or whereceach curve meets the straight. Either way should suffice, 6ft isn’t very long. The loops would be 15ft or less over all. 
I’d put in a third terminal strip under the yard, fed from the other nearby one.

While optional, you could feed the yard terminal strip separately from the DCC base, with a DCC circuit breaker and gap the rails at the yard entrance. The benefit would be any derailment/short in the yard will not kill power to the loop, or vice versa. But it’s not necessary on a small layout really. I only mention it because it’s good practice/habit. As you’re just getting started in the hobby, it’s the best time to form good habits.


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## gregc (Apr 25, 2015)

REdington said:


> The general rule of thumb is each piece of track needs feeders attached.


but if you solder every other railjoiner and solder feeders to them you only need half as many feeders


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## Scoba-01 (2 mo ago)

Darrkon said:


> Hi all,
> I am new to the forums and model railroading and in the process of building my first proper layout. I was going to stick with DC using two controllers (one for an inner loop and one for an outer loop) with the loops joined by turnouts that were insulated from each other. But I couldn't picture how a train would move from one loop to the other and decided to go to DCC.
> 
> The layout is basically a big loop. Inside the big loop is a smaller loop with one set of turnouts to join them together. Outside of the big loop will be a small siding connected to the big loop by turnouts - this will be a little 'yard' type area for small trains and carriages to move around. The turnouts will be PECO insulfrog but I was NOT planning to use any insulated joiners between them (unless someone says I should).
> ...


Check out NCE -DCC, to me the Best Practices go to this company, "None of our products are ever obsolete from day one of manufacture"! Direct from the owner and designer to me in 1995! That is why I have promoted & sold their product for over 25 years now. There are others yet to me NCE gives you all the control you need in one hand, bar none!


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## mesenteria (Oct 29, 2015)

Darrkon said:


> Hi all,
> I am new to the forums and model railroading and in the process of building my first proper layout. I was going to stick with DC using two controllers (one for an inner loop and one for an outer loop) with the loops joined by turnouts that were insulated from each other. But I couldn't picture how a train would move from one loop to the other and decided to go to DCC.
> 
> The layout is basically a big loop. Inside the big loop is a smaller loop with one set of turnouts to join them together. Outside of the big loop will be a small siding connected to the big loop by turnouts - this will be a little 'yard' type area for small trains and carriages to move around. The turnouts will be PECO insulfrog but I was NOT planning to use any insulated joiners between them (unless someone says I should).
> ...


I have powered a spur that ran off one corner of my folded loop track plan with a single feeder pair at the proximal end (nearest the layout and bus). The spur was a total of 14 feet long, and ended as a stub yard with five ladders. So all this was fed with a single pair of 22 gauge feeders, but where the stub left the layout. I never had problems powering or signaling to the decoders parked in the yard at the other end.

What I mean to suggest is, if your layout is well connected, properly soldered with feeders, and the feeders are robust enough in size to take what you're trying to shove through them, you should have no problems with power and reliability in signaling commands to the decoders running in those controlled lengths of fed trackage. As a result, I only power every six-to-eight feet of contiguously connected trackage with one pair of feeders. When the distance around either direction from the command station exceeds 10 feet, I resort to a bus, usually of 14-gauge solid core copper. I usually run my bus split, running left and right from the command module, rather than run one long bus either clockwise or the other way.

While trying to envision what you are describing, I might go for a single bus running one way around the perimeter of the layout, underneath, and then maybe four pairs of feeders, one of which would go to your siding. The other distances should not suffer unduly with one pair of feeders at either end of the large oval and a single pair feeding the inner. I think you'll be fine.


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## REdington (Aug 20, 2018)

mesenteria said:


> I have powered a spur that ran off one corner of my folded loop track plan with a single feeder pair at the proximal end (nearest the layout and bus). The spur was a total of 14 feet long, and ended as a stub yard with five ladders. So all this was fed with a single pair of 22 gauge feeders, but where the stub left the layout. I never had problems powering or signaling to the decoders parked in the yard at the other end.
> 
> What I mean to suggest is, if your layout is well connected, properly soldered with feeders, and the feeders are robust enough in size to take what you're trying to shove through them, you should have no problems with power and reliability in signaling commands to the decoders running in those controlled lengths of fed trackage. As a result, I only power every six-to-eight feet of contiguously connected trackage with one pair of feeders. When the distance around either direction from the command station exceeds 10 feet, I resort to a bus, usually of 14-gauge solid core copper. I usually run my bus split, running left and right from the command module, rather than run one long bus either clockwise or the other way.
> 
> While trying to envision what you are describing, I might go for a single bus running one way around the perimeter of the layout, underneath, and then maybe four pairs of feeders, one of which would go to your siding. The other distances should not suffer unduly with one pair of feeders at either end of the large oval and a single pair feeding the inner. I think you'll be fine.



But have you done the quarter test (shorting the rails) to make sure the the breaker trips on all those tracks farest away from the feeders???? It's not getting the power to the track, it's making sure the power overload trips so there is not a melt down. I melted a Kato F 3 (N scale) truck when it became shorted on a frog. It was so bad it had a small flame for a second. 
So I'll say it again. Do the quarter test....


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## Darrkon (2 mo ago)

Thank you all for the great advice and suggestions on how to wire up this layout! Really appreciated.
The way I’ve built the baseboard limits access to the underside of it. It’s basically plywood on timber frame resting on ikea tables. To access underneath I have to slide it forward. I can fish cables from anywhere on the board to the front (with underside exposed) then perform any wiring here.
I’m thinking of installing a pair of bus bars wired up to the controller, then running point to point wiring to each of the drops. This will use a lot more wire than a bus layout, but will make my job a bit easier since everything happens at the front of the board.
I’m also thinking of using 18 gauge stranded wire from the bus bar to the track location then 22 gauge solid core wire for soldering that to the track. I read solid core wire is easier to work with when doing this (I had trouble soldering some test stranded wire to test track).
None of this is set in stone if anyone thinks it’s a bad way to go. I could potentially get the whole thing out to run a bus wire instead. 
I’ve attached a pic of what I have so far anyway, along with some track shown for the planned yard area and small station (once I figure out how to build up those parts level with the track. 
Thanks again for the great advice!


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## gregc (Apr 25, 2015)

REdington said:


> I melted a Kato F 3 (N scale) truck when it became shorted on a frog. It was so bad it had a small flame for a second.


what caused this problem and how did you fix it?


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## REdington (Aug 20, 2018)

Going through a turnout from the frog end and it was thrown for the other direction, causing a dead short on the frog. I was using 28 gauge wire (cause that's what I had on hand) for the frog and it wasn't heavy enough to pop the circuit breaker. I'm using 10 amp boosters that at that time, was without any other circuit protection. Now each block has a 3156 bulb for protection. I also I switched to 22 gauge wire for all feeders. That happened over 10 years ago and since I changed to heavier gauge wire and added 3156 bulbs, I haven't had any other problems or melted trucks.


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## J.Albert1949 (Feb 3, 2018)

Based on the pic in post 9 above...
You don't really need "a bus".

Just run feeders to the inside and outside tracks at the back.


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## mesenteria (Oct 29, 2015)

REdington said:


> But have you done the quarter test (shorting the rails) to make sure the the breaker trips on all those tracks farest away from the feeders???? It's not getting the power to the track, it's making sure the power overload trips so there is not a melt down. I melted a Kato F 3 (N scale) truck when it became shorted on a frog. It was so bad it had a small flame for a second.
> So I'll say it again. Do the quarter test....


Yes, I did. I knew to do it because I would have been hard-pressed to replace decoders if I got a hard short and lost any number of them.


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## Conductorkev (Nov 5, 2021)

Those tunnels that you have you should allow access to the inside of them just incase I'd derailment inside of them. The last thing you need is a train stuck inside one and the only choice is to tear it up.


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## gregc (Apr 25, 2015)

mesenteria said:


> Yes, I did. I knew to do it because I would have been hard-pressed to replace decoders if I got a hard short and lost any number of them.


not sure how a short can damage a decoder ... the short is not thru the decoder, it's between the rails which means there's no voltage to decoder


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## Darrkon (2 mo ago)

I’ve ended up putting those bus bars under the table and running some 18awg wire to form two drops to the big loop and two to the small loop. They run to the far left and right sides.
I haven’t hooked it up yet as I’m waiting for the flexi track to arrive, but I guess I could use the practice soldering to track. 
It took me a minute to work out ‘quarter’ test meant putting a coin on the rails! (That is it isn’t it?)
As for tunnel access - that’s been bugging me too. Once there is a landscape built on top I’ll try to work in a building over it to disguise an access hole. I’ll do some more reading up on tunnel access and construction. Those are just something I threw together for now.
Cheers!!


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## DonR (Oct 18, 2012)

You can use a quarter...or any metal such as a screwdriver
or pliers put across the 2 rails.
It will produce a short circuit and your controller should
react to it.

Don


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## Conductorkev (Nov 5, 2021)

Darrkon said:


> I’ve ended up putting those bus bars under the table and running some 18awg wire to form two drops to the big loop and two to the small loop. They run to the far left and right sides.
> I haven’t hooked it up yet as I’m waiting for the flexi track to arrive, but I guess I could use the practice soldering to track.
> It took me a minute to work out ‘quarter’ test meant putting a coin on the rails! (That is it isn’t it?)
> As for tunnel access - that’s been bugging me too. Once there is a landscape built on top I’ll try to work in a building over it to disguise an access hole. I’ll do some more reading up on tunnel access and construction. Those are just something I threw together for now.
> Cheers!!



I usually have Mt tunnels at the back of the layout leaving a lil room for me to get behind the layout. I leave the back open since it won't be seen unless your behind the layout. Last time I used Woodland scenic sharper sheet to form mtn and put a peak and then the other side Cameroon just a little bit leaving me enough room to work inside. I didn't even need to frame the man as sharper sheet with ws plaster cloth made it so it never folded in on itself.


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## Darrkon (2 mo ago)

Conductorkev said:


> I usually have Mt tunnels at the back of the layout leaving a lil room for me to get behind the layout. I leave the back open since it won't be seen unless your behind the layout. Last time I used Woodland scenic sharper sheet to form mtn and put a peak and then the other side Cameroon just a little bit leaving me enough room to work inside. I didn't even need to frame the man as sharper sheet with ws plaster cloth made it so it never folded in on itself.


This is a great idea and gave me an idea. If I move the tunnels to the left hand side of the board (where there is easy access to the side), instead of building two enclosed tunnels - I can just build 6” sections of the tunnels at the start/end which open into a larger open sided box (or hollow landscape) that gives access to both tracks. Finish with some profile boards and a hinged door - done.
Thanks for the inspiration!


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## mesenteria (Oct 29, 2015)

gregc said:


> not sure how a short can damage a decoder ... the short is not thru the decoder, it's between the rails which means there's no voltage to decoder


I don't really understand it either. All I know is that the late Randy Rinker over on MR forums (COVID Causalty in 2020), who was an electrical engineer and was our resident DCC guru over there, warned about 'hard shorts' letting all the 'magic smoke' out of decoders. He flogged the quarter test often, saying that it was to avoid the magic smoke leak due to a hard short. I'm not in a position to argue one way or another as STEM wasn't my métier in an earlier part of my life.


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## Conductorkev (Nov 5, 2021)

Darrkon said:


> This is a great idea and gave me an idea. If I move the tunnels to the left hand side of the board (where there is easy access to the side), instead of building two enclosed tunnels - I can just build 6” sections of the tunnels at the start/end which open into a larger open sided box (or hollow landscape) that gives access to both tracks. Finish with some profile boards and a hinged door - done.
> Thanks for the inspiration!



Np glade I could help. My thoughts is that it is much much better and easier than doing a pullout or a hinged....


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## Darrkon (2 mo ago)

So I’ve now built this cardboard thing - you can kind of see on the left that the side is open. I can reach in there to either set of rails and get stuff out. It ain’t pretty but hopefully it will do the job. At either end I’ll build 2” long entry/exit tunnels when I have my portals. 

So this is still on topic - you can see a piece of wire for a DCC feed inside.

On the quarter test front - I bridged the rails for a second with a screwdriver and there was a spark, the trains stopped but then everything started up and was fine. Is that normal? I was expecting the controller to shut down. Is the idea to leave the short on for longer and see what happens? Should I do this with or without trains on the track?

Cheers!


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## Conductorkev (Nov 5, 2021)

Darrkon said:


> View attachment 593181
> 
> So I’ve now built this cardboard thing - you can kind of see on the left that the side is open. I can reach in there to either set of rails and get stuff out. It ain’t pretty but hopefully it will do the job. At either end I’ll build 2” long entry/exit tunnels when I have my portals.
> 
> ...



Here is a front view of my mtn before I tore it out. It wasn't done and never fully completed. I never put in the river that went between the peeks 3 waterfalls (there's one in between the peaks you can't see from this angle and two right there that is split by that Boulder.) Plus would have added trees on the mtn also. But behind it I could access any train derailment which before I tore it out happened often. Which leads to another suggestion. Do very rigorous testing before installing mtn. After that you don't want to make any changes that could mess up alignment inside there like my dumb [email protected]@ did. I was changing some track around and somehow the track shifted inside there. I could never fix properly to make it work 100%.


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## REdington (Aug 20, 2018)

Darrkon said:


> On the quarter test front - I bridged the rails for a second with a screwdriver and there was a spark, the trains stopped but then everything started up and was fine. Is that normal? I was expecting the controller to shut down. Is the idea to leave the short on for longer and see what happens? Should I do this with or without trains on the track?
> 
> Cheers!


No, that isn't normal for most DCC systems. Most systems trips the protection circuit instantly and then a couple of seconds to reset. 
A test you could try is, short the output at the command station/ booster and see if it has a beeper or a light to indicate a short.
Once you know the reaction of you system, you can then do the quarter test to see if you need more track power feeders


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## Darrkon (2 mo ago)

ConductorKev - that layout was looking pretty good, sorry to hear you had to tear the mountain up and good advice on testing thoroughly before mountain construction. I'll be using flexi track and track beds, etc.. all sorts of things I have never used before. I think my mountain will stay as cardboard held in place with pins for quite a while before I build anything permanent on or around it. Even before the track and bed is glued down.

REdington - Thanks again. I'll give that a go today, starting by shorting the wires right out of the controller to see what happens, then test again at the farthest part of the track and compare. I'll also re-test once I get the drop wires soldered up.

Cheers


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## dtozer67 (2 mo ago)

Darrkon said:


> Hi all, I am new to the forums and model railroading and in the process of building my first proper layout. I was going to stick with DC using two controllers (one for an inner loop and one for an outer loop) with the loops joined by turnouts that were insulated from each other. But I couldn't picture how a train would move from one loop to the other and decided to go to DCC. The layout is basically a big loop. Inside the big loop is a smaller loop with one set of turnouts to join them together. Outside of the big loop will be a small siding connected to the big loop by turnouts - this will be a little 'yard' type area for small trains and carriages to move around. The turnouts will be PECO insulfrog but I was NOT planning to use any insulated joiners between them (unless someone says I should). The entire layout board is 120 x 180cm (or 6 x 4) and if I run one set of wires from the controller to the track, I can run a couple of trains reasonably well (though at some points the trains seem a little jerky in their movements). I put the jerkiness down to some track pieces being very old with poor fitting fish plates and potentially needing to use bus wiring to more points on the rails. It could also be the decoders or the controller I guess - those are just basic Hornby 4 pin decoders a Hornby Select controller. I am planning to replace most of the big loop with flexi track - this will reduce the number of joins/old rail. But the questions I have are:
> Do I need bus wiring for a layout of this size? (I suspect this is a yes)
> If I do implement bus wiring, do I need to break each of the rail loops with a set of insulated joiners (I could not find a clear answer on this) I understand the bus wire itself does NOT make a loop, but the rails will make a loop.
> What would be the suggested number of drops for a layout of this size? I see some people say one per track piece, others say every 1m/3ft.. I am thinking 5 or 6 - two per loop and two for the yard area
> Thanks in advance for any/all input with this! Cheers!


1)Buss is best as any track joint can cause problem, along with track/wheel dirt! 2) All track is live no insulators are needed as long as you do not have a reversing loop. Then you would need a manual or best is Auto-Reverser/Booster (see NCE info) 3) Any new section of track where mechanical electrical joint. 4) This is a great solution to any erratic locomotive control issue, "equip locomotive with "Keep Alive" decoders or add on unit. Basically capacitor bank, stores electric charge to power the decoder when contact with track is temporarily lost. 5) Keep track clean, dc or dcc does not matter, Required and especially with DCC signal on track. 6) Suggested under base Buss wire size 14 AWG, house wire works, cheap, well no copper is cheap! 7) Terminate one end of your Buss with a 0.001 microfarad capacitor, cancel unwanted electrical noise, "unwanted interference "! 8) Good practice is to place a device called an MOV across Buss, 32 volt device, clips very high voltage spikes to 32 volts which decoder electronics can tolerate. Reduce unexplainedd decoder malfunction, address loss, or complete damage. "Good Practice"!


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## Darrkon (2 mo ago)

So I tried shorting the wires right out of the controller yesterday afternoon - nothing happened? No spark, no powering down of the controller - absolutely nothing 
I plugged it in to the single power connection the track has at the moment, got two locomotives up and running then ran some short circuits at various points around the track. Each time there was brief spark and the trains would stop, but once the short was cleared, the trains would resume operation. I can only assume that is expected behaviour and that it is avoiding permanent damage by just cutting track power until the short is cleared.

Thanks for the info dtozer67. I've ended up running point to point wire to the various drops so hopefully that will be sufficient for my little setup.

Today my flexi track lengths, insulfrog points and tunnel portals arrived. I think I need to open a thread in 'My Layout' - I've already learned something about tunnel portals - they are not just a hole, they are also surrounding material (which in my case now blocks the adjacent line because I moved the tunnels). LEARNING!

Cheers


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## dtozer67 (2 mo ago)

Darrkon said:


> So I tried shorting the wires right out of the controller yesterday afternoon - nothing happened? No spark, no powering down of the controller - absolutely nothing
> I plugged it in to the single power connection the track has at the moment, got two locomotives up and running then ran some short circuits at various points around the track. Each time there was brief spark and the trains would stop, but once the short was cleared, the trains would resume operation. I can only assume that is expected behaviour and that it is avoiding permanent damage by just cutting track power until the short is cleared.
> 
> Thanks for the info dtozer67. I've ended up running point to point wire to the various drops so hopefully that will be sufficient for my little setup.
> ...


Consider joining MERG group.
Lot of good information on model electronics. Also JMRI, great for DCC programing & operations.
NCE have some great information on DCC operations & products. Ed Wilson is the technical support for NCE Products
Cheers & Good luck!


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## vette-kid (May 2, 2020)

No, you really don't need extra feeders for that layout. I ran 2 loops at 4x12 with just one set of wire connected to it just fine. I only ran 2 locos at once, which I suspect is the most you would normally run on that. 

Extra feeders are insurance against poor rail connections and are easy enough to add, but aren't really needed. The only reason I have multiple feeders on my 4x12 is that it's the easiest way around the kato power routing switches. 

Sent from my SM-G781U using Tapatalk


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## Severn (May 13, 2016)

I ended up soldiering all my joiners on all my flex track, except where it's just some kato plastic base track end to end. I soldered the ends at the transition though.


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## REdington (Aug 20, 2018)

vette-kid said:


> No, you really don't need extra feeders for that layout. I ran 2 loops at 4x12 with just one set of wire connected to it just fine. I only ran 2 locos at once, which I suspect is the most you would normally run on that.
> 
> Extra feeders are insurance against poor rail connections and are easy enough to add, but aren't really needed. The only reason I have multiple feeders on my 4x12 is that it's the easiest way around the kato power routing switches.
> 
> Sent from my SM-G781U using Tapatalk



If your track doesn't pass the quarter trick (shorting the rails so the overload kick out), you need more feeders. For instance, when a loco shorts out on a powered frog going the wrong way than it was set for. Here what can happen.


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## Darrkon (2 mo ago)

Thanks for the extra information!
I do have insulfrog turnouts - so the extra wiring ended up being necessary anyway (and indeed I will need even more for all of the sidings and etc I plan to build). But it hasn't helped with some jerkiness the locomotives experience. I will put this down to crappy DCC decoders, controller, wheel pickups, etc..
I am using flex track and soldering the joints that occur in curves, so there are not an excessive amount of track sections.

It has all been fun to learn anyway - flex track, soldering track, etc.. so all good.

My build has kind of stalled over the festive season but I am hoping to ramp up soon and finish track laying soon and hopefully get some photos into the 'my build' forum for some feedback and tips.

Cheers all!


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