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Wiring conventional block control for future DCC in N scale

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Wiring conventional block control for future DCC in N scale
Posted by videobruce on Wednesday, January 18, 2012 3:00 PM

I would like to go DCC, but I already have 23 locomotives that would need a full modification that I don't want to do. Trouble & expense to me isn't worth it.
So, what I see as my only option, is to wire for conventional block control with the assumption, in the future I will go DCC with future newer units that either have the DCC included or can be switched over to DCC by drop in decoders selling the existing units if I can.

My question is, should I 'gap' each block for both rails even though I don't need to for conventional block control now for the future and just tie all the common rail leads together for now? There are no reverse loops. The layout is a 9x19' 'J' shape.

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  • From: North Dakota
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Posted by BroadwayLion on Wednesday, January 18, 2012 4:16 PM

You should not need to gap both rails since DCC does not require any gaps.
I wired my layout this way, even though the likelihood of my ever using DCC was beyond zero.

To do it you would just bind all of your blocks together into a single block, or just switch them all to CAB-1 and install your DCC on CAB-1 and that should be sufficient.

 

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by wp8thsub on Wednesday, January 18, 2012 4:34 PM

By the time you wire the layout for conventional block control, you could easily end up spending as much as if you went DCC.  All the wire and electrical components needed for block control add up surprisingly fast.  It isn't necessary to place a decoder in every loco at first.  Do a few, and wire a switch to change the power from DCC to a DC power pack so you can run your DC stuff, and have a few more to kill power to tracks where you have the decodered locos stored when you run on plain DC.  I'm not sure if you'd find this option workable, but thought I'd suggest it...

Rob Spangler

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Posted by videobruce on Wednesday, January 18, 2012 4:39 PM

It was my understanding for troubleshooting, gapping both rails for DCC was necessary.

Wire I have or could get and toggle witches aren't that expensive. I understand it's kinda doing double work, but I don't want to shell out one or two large to replace all my power. I'm sure I will take a bath on selling what I have.

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Posted by fwright on Wednesday, January 18, 2012 4:55 PM

videobruce

My question is, should I 'gap' each block for both rails even though I don't need to for conventional block control now for the future and just tie all the common rail leads together for now? There are no reverse loops. The layout is a 9x19' 'J' shape.

The only occasions that need gaps in both rails in DCC are reversing sections (you have none) and for separation between multiple boosters and associated power districts.  Since you are unlikely to need more than one 5 amp booster, there would be no need for gaps at all.

The downside of no gaps is that a short circuit shuts down the entire layout.  But a single booster with multiple subdistricts supplied through multiple circuit breakers will work just fine.  As long as it is a single booster common rail is good, and your existing blocks can each be powered through their own circuit breaker.  Or just use the toggle switches for problem isolation in DCC.

The biggest concern is wiring robust enough to pass the quarter test.  You need sufficient feeders to keep the voltage drop minimal everywhere so that the quarter test can be passed.

Fred W

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  • From: Colorado
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Posted by fwright on Wednesday, January 18, 2012 4:55 PM

videobruce

My question is, should I 'gap' each block for both rails even though I don't need to for conventional block control now for the future and just tie all the common rail leads together for now? There are no reverse loops. The layout is a 9x19' 'J' shape.

The only occasions that need gaps in both rails in DCC are reversing sections (you have none) and for separation between multiple boosters and associated power districts.  Since you are unlikely to need more than one 5 amp booster, there would be no need for gaps at all.

The downside of no gaps is that a short circuit shuts down the entire layout.  But a single booster with multiple subdistricts supplied through multiple circuit breakers will work just fine.  As long as it is a single booster common rail is good, and your existing blocks can each be powered through their own circuit breaker.  Or just use the toggle switches for problem isolation in DCC.

The biggest concern is wiring robust enough to pass the quarter test.  You need sufficient feeders to keep the voltage drop minimal everywhere so that the quarter test can be passed.

Fred W

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Posted by john.pickles87 on Wednesday, January 18, 2012 5:10 PM

Hi Bruce,

I've an N Gauge 8ft x 2ft time saver made up of about a dozen blocks wired for DC (2 controllers,any more an it gets complicated).  With all block DPDT's thrown one way and we run up to 4 MRC controllers and have some real fun. 

Do not try to mix em, it's either DC or DCC.  The club I'm with is building a US prototype HO Exhibition layout with 18 blocks on DPDT switches across the front wired the same so we can run older DC when we want and still run DCC at shows. We always double gap on blocks as standard.

Be in touch.

pick.

?
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Posted by videobruce on Wednesday, January 18, 2012 5:43 PM

The downside of no gaps is that a short circuit shuts down the entire layout.

Thats' why I thought it was necessary. Easier to do it while under construction that later.

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Posted by rrinker on Wednesday, January 18, 2012 6:12 PM

 Double gaps betwene sections pwoered by different boosters or by different sections of a multiple output circuit breaker. Single gaps for detection circuits for signals.

 Not sure what the big deal is, 1 gap or 2. I always double gapped my layouts for DC as well, I really REALLY hate common rail wiring. One gap or two, it;s no big deal, a few extra seconds with the Dremel or some extra plastic joiners.

                        --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by videobruce on Thursday, January 19, 2012 7:32 AM

It's not the gapping, it's the additional wiring.

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Posted by Ron High on Thursday, January 19, 2012 9:46 AM

I have an HO DC block cab control system and I use common rail .What I do differently is gap both rails and run a common rail bus # 14 or 12 gauge with connections to the rail that is considered the common.This is done to every block that is controlled through my cab control panel No problems missing gaps and a more positive electrical connection . The connection from the common rail bus to the common rail is made through a small terminal block with a small gauge short wire jumper  to the rail in the  block,this gives me a test point to trouble shoot. This maintains the advantage of less wire and means you need only wire one set of contacts on your toggle or rotary switch. You will also have the common side on a bus wire arrangement if you ever convert to DCC (NOT ME).

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Posted by videobruce on Friday, January 20, 2012 6:49 AM

We seem to be on the same page here.

This was what I was planning to do for now (if I don't go DCC). Plan for DCC, but wire for DC.

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