Converting a DC layout to DCC

[rrlcommish]

OK, I'm taking the plunge.  I have a relatively small layout (for now)...4x8.  I used Atlas snap track and terminal track for power feeds.  The layout is divided into 8 blocks, so there are 8 terminal track feeds.  The layout runs very smooth and is in a climate-controlled part of the house, so I'm not concerned about alot of track expansion/contraction and resulting voltage drops.  So I am thinking I'll just run the feeds from the DCC power supply to each of the 8 terminal tracks.  I'll have to double-insulate one of the spurs to make it a programmming track, but that won't be hard since I never ballasted that siding.  Anyway, my question is...what is the best way to run the wiring?  Should I run a "bus" to a terminal strip at the center of the plywood underneath and then branch out to 7 terminal tracks and then just run one feed from the programming terminals on the DCC to the 8th (programming track) terminal?  Or should I just run a 14 AWG bus around the layout and run smaller 22 AWG feeders to the terminals like many folks do?  Or is there an even easier/better way that I'm not thinking of?  Is 14 AWG too much for this small of a layout?  And then how do I power the turnouts (Atlas Snap Switches), with my old DC pack?  Oh, and for the record I will either choose NCE PowerCab or Digitrax Zephyr as a starter system.  Just haven't been able to decide which is better (despite the ad nauseum discussions on this forum about which is better), as they are both so good.  Digitrax seems better for long term expansion and accessory decoders but NCE is just so darned easy to use.  Any and all suggestions are welcome.   Thanks!  Jim

[tstage]

Jim,

It already sounds like you've done your homework on DCC systems.  Yes, either the Zephyr or the Power Cab will be very good choices for you.  I chose the Power Cab because it was more intuitive - to me.

Like you, I have a 4 x 8 layout but I started pretty early on with DCC. It sure makes operating trains a lot 'o fun.

Tom

[WSOR 3801]

 Just hook up the system to your existing wiring and do the quarter test.  If it trips every time like it should, you are good to go.  Use the old pack for turnout power.

Here is my roughly 4x8 table.

My system.  I went with a Zephyr, as my dad and the club also use Digitrax.  The programming track is the piece of Ez-Track with the wire hooked to it.  

With the Zephyr (and Super Chief), you can program on the programming track and still run trains everywhere else.   I don't think you can do this with the NCE, the trains must come to a stop.  I know Lenz requires the trains to stop. 

[jeffrey-wimberly]

davidmbedard

 Is your layout running reliably with DC right now?  If it is, unplug your DC power pack and hook up the exsisting wires to the DCC system.  Take a quarter with your DCC system on and short out every piece of track.  If your system 'trips' every time you do the quarter test, then you are golden.

What he said!

[MisterBeasley]

A track power bus will give you a more reliable, "clean" digital signal.  However, on a small layout you probably couldn't tell without putting an oscilloscope on it.  I've got a 5x12 foot layout, and I used 18 AWG for my track power bus.  It works fine.  But, if you've already got your layout wired and it works, just plugging it into the DCC system is all you'll need to do.

Why do you have all the blocks?  Are they isolated so you can run trains independently on each, or are they just equipped with shutoffs for "idling" engines?  Do you use them for signalling and block detection?

I would leave your turnouts exactly as they are.  You can keep them on the same power supply, and use the same controls.  Don't use your DCC supply to power turnouts - save it for the trains themselves.  DCC allows you to add "stationary decoders" which will allow you to run your turnouts from your throttle, but it's not necessary to do this, and many of us choose to stick with old-fashioned control panels.

[rrlcommish]

The blocks are mostly for "idling" engines, though I switch a couple industries independently as well so I guess the answer is "both".  Here is the thing I don't understand about just plugging in the DCC system to my existing wiring...each of those blocks is electrically isolated via insulated rail joiners on one of the rails.  I am using an Atlas Selector to turn blocks on and off.  If I just hook straight to the new DCC power, do I need to just flip all my selectors to "A" (or "B", it doesn't matter so long as the block gets power) and leave them there?  Or am I missing something electrically here?  Each terminal track has a power feed but I only have one common rail feed to one of the terminal tracks, no other common feeds were necessary.  I am using an MRC 280 dual-cab power pack, thus the need for A-B Selector so I could run two trains independently.

[Texas Zepher]

rrlcommish

Here is the thing I don't understand about just plugging in the DCC system to my existing wiring...each of those blocks is electrically isolated via insulated rail joiners on one of the rails.  I am using an Atlas Selector to turn blocks on and off.  If I just hook straight to the new DCC power, do I need to just flip all my selectors to "A" (or "B", it doesn't matter so long as the block gets power) and leave them there?

Yes, connect the two output wires from DCC unit where the current "A" cab two wires are connected.  Flip all the selectors to "A".

I am using an MRC 280 dual-cab power pack, thus the need for A-B Selector so I could run two trains independently.

I would totally remove the MRC 280, so that the "B" cab wires are connected to nothing.  With common rail wiring you don't want to take the chance of having one of the selectors accidentally getting flipped to "B" and get some sort of feedback through the "B" cab.