Help with layout

[jward]

each pack is its own circuit. as such they won't short out if you only have one terminal on each connected together. the + and - are irrelevant, as when they are both in use they will often be different polarities anyway. this principle is also widely used in electronics where power supplies often have a positive, a negative, and a ground side. as long as each section of track is connected to no more than one controller they won't short regardless of which polarity each is set at. as long as you don't bridge the gaps between blocks connected to separate controllers, such as having a locomotive stopped on the gaps, you will be fine.

[jbrock27]

I get that it is a matter of it will work either way, but isn't is universally understood to approach and set it up in the manner I described?
And since I believe that is the case, would it not make it easier to find references when looking to solve any problems that come up?

[jward]

it would make sense if both power supplies were constant polarity, which the controllers are not. but even then, as in the case of batteries, you can put the + end of one and the - end of the other to the common or ground. there are instances where that is an advantage. in the case of block control the only advantage is if it helps you understand your wiring better. if "right hand positive" helps you then wire the left terminal on each pack to common. it is not wrong to do it that way. the important thing is that both terminals on a particular controller are NEVER connected to the same rail without some insulator between the connections.

which brings up something to watch for with ez track. the plug in connectors are reverseable, so if you are not careful when adding feeders to the track you can get them flipped so that you are connecting both positive and negative to the same rail. it is a good idea to use a cheap ohmmeter to look for short circuits before you turn the power on. when wiring my layout, I colour code the connections to avoid problems. you can do this with a paint marker to mark one conductor on the ez track connection cable. I also test everything each time I make a connection so that any problems I have I know to look at the last thing I wired.

[jbrock27]

You hit the nail on the head; it is easier for me to use black as my Common and to - and red as my Power wires to +.  I would suspect it would also be easier for most folks but maybe not.  I get it.  When I give this advice, I am always thinking in terms of my MRC controllers.  There is also a great YouTube I found that makes is super easy to understand Common Rail wiring.

[Desertdweller]

Hunt,

There are several good reasons to wire a model railroad for DC instead of DCC.  If the wiring cost for DCC is lower than for DC (and I'm not sure that is true), that would be its only savings.  DCC requires at least as many track feeder connections as DC in order to maintain reliable operation.  The early claim that "you can run your whole railroad with two wires" is no more true with DCC as with DC.  You could wire a DC railroad with two wires also, but operation would be poor and limited.
 
Good reasons to use DC:  All model locomotives can operate on straight DC without modification.  Straight DC or "DCC ready" locomotives are priced lower than DCC-equipped locomotives.

DC requires no expensive throttles, power boosters, or locomotive-mounted receivers.

DC locomotives require no programming.

DC block wiring requires only DPDT block selection switches for each block.  Electric block isolation is desirable for DCC as well.

DCC requires power to be on all tracks at all times, unless track blocks can be isolated and turned off.  This presents a potential safety hazard.  I once had an HO 2-8-8-2 ruined by a scheme like that when it malfunctioned and melted the centers out of all drivers when stalled on a section of track that was supposed to be dead.

DC wiring requires no components that cannot be isolated, wired around, or circuits traced by eyeball.  No electronic components that can fail unseen, except for those in the power pack itself.

DC wiring is not subject to interference by outside radiation or emf forces.

Money saved by using DC can be spent on other desirable model railroad purchases: additional locomotives, cars, trackwork, scenery.

I built a fairly large N-scale model railroad several years ago from scratch with DC wiring.  I had about 60 locomotives that were DC only.  With DCC, each one would have had to be converted to DCC or retired.  As it was, the only modification I made to them was to install diode-controlled directional lighting on those that were not so equipped.

I don't think you should give the impression that only "serious" or "real" model railroaders build DC railroads.  I have been a model railroader since 1968, an N-scaler since 1978.  DC model railroads have been around for 100 years.  It is a proven technology.  I could have built my present railroad for DCC operation, could have afforded to, but did not for the reasons listed above.  I think there are still more DC model railroads than DCC, and more are continuing to be built.  It is not obsolete technology, it is simple and foolproof.  I am glad that the manufacturers recognize the continuing demand for DC components, and continue to offer them.

Les

[Len]

And if you want to add DCC at a later date all you have to do is swap out a power pack for the DCC system and turn all the blocks on. Some folks even connect the power pack and DCC system to a DPDT toggle switch so they can go back and forth without disconnecting anything.

For those just starting out that need to figure out reverse loops and such: https://kalmbachhobbystore.com/model-trains/books/12491__Wiring-Your-Model-Railroad

Len

[jbrock27]

You could wire a DC railroad with two wires also, but operation would be poor and limited.
Les

Actually funny you say that.  I am in the process of corking my L shaped, DC layout.  Before beginning the corking, I had one terminal track section wired up in order to test what I had laid out and had no operational problems whatsoever.  My plan when done is to have it wired in 2 maybe 3 locations for the main run with other locations on blocks with 1 power wire to them as they are farily short.  I have soldered most but not every rail joiner.

I otherwise agree with you Les on what you say about many serious RRers running DC and DC in general.  The sound from DCC just does not do it enough for me to get into it at present. 

[Hunt]

Les,
Having used both for many years, to use DCC or DC is a preference for me in the same perspective as using a car or a horse for transportation.  A few individuals in my model railroading community use DC.  One has DC at home and uses DCC at the club (he spends all his time running his trains at the club).

I used DC Cab Control for many years but was always looking for something better experimenting with various digital control products. I changed to DCC around 15 ago to be able to run any locomotive in any direction independent of where it is on any given track.  I started taking advantage of being able to tune the running characteristics of the locomotive when it became available. So control your track with DC Cab Control,  I'll control my locomotives using DCC until something better comes along. Locomotive wireless control using Bluetooth technology may become another option.  At this time, those using model train as part of their Christmas decorations can have sounds without having to use DCC.

[jward]

my perspective is similar to hunt's. I got into dcc as a way to tweak the performance of my locomotives. I have always felt that the "simplicity" of dcc was oversold, and the operational possibilities not fully explained. thus, I have always wired my layouts for dc, even if I run dcc. the only change in my wiring to accommodate dcc is the use of 18 guage wire instead of the 22-24 guage telephone wire I was using.

[Desertdweller]

jbrock, jward, Hunt: 

The issue with having multiple feeder lines, aside from creating isolated track sections, is voltage drop.  Rail of any material is a poor conductor compared with copper wire.  And that wire must be heavy enough to carry the current required without heating up or creating voltage drop. I suggest 18 gauge wire as a minimum size for power connections to track.

I would suggest if anyone was planning to go to DCC at a later date, build and wire the layout for DC.  As has been described already, it would be easy to convert a DC-wired railroad to DCC.  Once a layout reaches a certain size, additional feeder wires will be needed for both systems.

It all comes down to what you want your trains to be able to do.  If for some reason, it is important to you to be able to independently control more than one locomotive in the same track block, then DCC would be the system to use.  For me, that would be a capability of dubious value.  Onboard, DCC-controlled sound likewise.  Locomotive-mounted speakers are just too small to sound realistic, at least to me.  I have found the Kato Soundbox system to be more effective.  It uses a fixed speaker system, with the larger speaker better suited for the low-frequency sounds.  It can also power a large speaker.

I don't think it is fair to compare DC vs. DCC as horses vs. automobiles.  Each system has its own strengths and weaknesses.  For me, who built a new layout while owning dozens of DC locomotives, it was a cost/benefit decision.  But if I had no existing locomotives, I still would have not built a DCC layout, for the reasons stated in my earlier post.
I am more interested in running trains than in having locomotives that do tricks.  I have been a model railroader for 47 years, and am a retired locomotive engineer with thousands of hours of running trains, so I have a good idea of what I trying to recreate.

Les

[jbrock27]

jbrock, jward, Hunt:  

The issue with having multiple feeder lines, aside from creating isolated track sections, is voltage drop.
Les

But I just reported I don't have that occur for DC layout with an outside loop of track that runs in the shape of an L (give or take) and using just 2 wires.  The size of the L is 8 x 10 x 4 x 6 x 4 x 4

Part of my reason for mentioning it was to underline the importance of soldering the joiners for good continuity.

PS-I'm not into Clubs, either.

[jward]

les,
two points I think you have overlooked. first, with regards to voltage drops on a layout wired for dc but running dcc (or dc) if this becomes an issue you can always add additional feeders to the same block. redundancy is your friend. actually my blocks are rather short in most cases, 6 feet or so but in the past as long as 10-12 feet. with feeders placed in the center of each block I have never had a problem with voltage drop.

the second point concerns operation and dcc. you aren't interested in your locomotives doing tricks. I don't want mine to roll over and play dead either. that said, dcc has a very important advantage for operation in the ability to program the speed curves on all your locomotives so they all run exactly the same. this makes it easy to set up and break down consists. you don't have to remember which locomotives run well together and which ones don't. you can run helpers on the rear of your trains to get them over the mountain, and have separate engineers for both sets of locomotives. all of this is difficult if not impossible to do with dc.