DCC wiring

Model Railroader Electronics and DCC
21

Thanks Jeffrey.

Can you solder track joints already in place or do you need separate them and put a little flux as you note in each joiner and then reconnect?

My current track feeder wire is the standard Atlas wire (I believe is 20-ga?) do I need to up this to heavier gauge. My layout is only current a 4x8 with a max of 3 trains running at any one time.

Thanks,

David

22

The 20 gauge feeders themselves are fine, as long as you keep them short.

If you don’t solder, you are eventually going to have issues, it’s just a matter of time.

Ideally, you would separate things, and then solder. But, if they are relatively clean, a little flux on a toothpick would probably run into the joint, and the solder would follow. Don’t buy into the idea that you need a high power iron. What you need is a good clean tip, a little flux, and relatively fine solder. Get it hot, hit it with the solder, and get out.

23

If the track is already down and in place then just put a little flux along the outside edge of the joiner and make sure it gets on the rail too. Touch the hot solder tip to the joiner, apply the solder then move on to the next one. The wire you have should be good. If you think you need something heavier you can use 18 gauge. Anything bigger is going to be harder to hide under the ballast.

24

when you say (short) what is short? 3 inches 18inches?? thank you for your time.

slow train Ed

25

Short, as in the length of feeders, should be long enough to go from the rails to the buss lines with a little slack. Who wants a bunch of taut wires?

26

Edit - when I wrote this I did not see the entire 2nd page of responses… I thought I was responding to the last post on the thread.

Yes, How long is the main line of the layout? Are we talking a 4x8 or a basement full?

  1. Run a pair of power wires along under the main track. This is called a power bus. Wires should be 14-18 gauge depending on length. The longer the bus needs to be, the heavier the wire (smaller gauge number) will need to be. Personally I always twist mine, but that is not necessary.
  2. Connect the wires of the power bus to the output of the DCC control unit. Test to make certain power is getting to the end.
  3. Every 6 feet or so run a set of wires from the power bus to the track. These are called feeder wires. This will mean that a locomotive will never be more than 3 feet (1/2 the distance between feeders) from power. Feeder wires can be lighter wire (like 20-22 gauge).
  4. If the power bus is going to be longer than 30 feet there could be issues, so then several things can be done:
    A. Move the DCC controller unit to the center of the bus (making two shorter segments on each end).
    B. break it into two put a gap in the rails, and add a DCC power block controller unit (Digitrax PM42, CVP zonemaster, etc.).
    C. break it into two put a gap in the rails, and add a DCC booster unit.
    D. add a terminating resistor.
    E. combinations of the above.

Don’t make it harder than it is. It is very simple.

Another comment. I normally use stranded wire for

27

That’s what I do - except I have feeders soldered to EVERY joiner on the layout. Now here’s why you should get a soldering iron and learn: for the price of 1 pair of terminal joiners, you can buy a whole pack (24 pairs) or regualr metal joiners, and solder your own wires to them. You don’t do this on the layout or in any other awkward position - I build up a supply sitting at my workbench.

–Randy

28

David, to back up just a bit and take a breath (‘cuz I can see yer turnin’ blue…), here is the scoop: the metal joiners and soldered wires, called terminal joiners, are a great idea, but they only solve part of the overall problem with joiners. I’ll explain…and this is where you take another breath. [:)]

The metals in the rails and the metals in the joiners are not the same. Basic metallurgy/chemistry will tell you that it means ion exchange over time. Add bits of grit, dirt, flexing joints as the heavy locomotives pass overhead time and time again, and the corrosion of the ion exchange…you can see that joiners are going to fail. Maybe two years out, but more likely six months out…if all our experiences count and we add them up. Joiners left by themselves just don’t hold up well over time…period.

Feeding the joiners is a good idea…great in fact, but if the rest of the joiner surface mated to the rail feet is corroded and not making good contact, of what use are those nifty soldered wires? They aren’t! So most of us eventually capitulate, pay homage to the rail gods, and agree that we mere mortals will have to find a more robust solution. What we do is solder the joiners to the rails, and this is done when the joint is already made and the rails are oriented and fixed into place with track nails or caulking…whatever.

You don’t need to solder every joiner. Instead, do every second joiner. That way, both lengths of track going either direction from that joint are positively powered. You can let the far next joiners over in each direction slide and provide your tracks with heat expansion and humidity expansion if you have fluctuations in those. They don’t need to provide continuity because those middle soldered joiners are doing that for you.

Yes, absolutely, you will get a soldering iron, burn your finge

29

Thanks Crandell … information overload … yes … and I’m turning a bit blue … but well worth the world of knowledge. Basic metallurgy/chemistry, eh? Its been over 20-years since 1st year chemistry in engineering school. LOL. Don’t remember doing that well in Chem Eng 101 … I guess that is way I stuck with civil engineering instead … airports (avator taken at LBPIA 2003), highways and international border crossings.

I have reviewed my layout plan for my simple two loop 4x8 layout and will probably layout a bus loop of 16-gauge under the tracks and place two feeders from each rail on each loop from the bus. The length between feeders would then be approximately 8’, which seems in order for the typical ranges I have read of 6 to 10 feet. If I feel I need more (constant) power, I can simple add more feeders. However, I currently run the layout with 18-blocks and common rail, and don’t have any issues, with slow areas.

With the recommendations herein and in hommage to the rail gods … I guess I have to break down and procure a solder and take a tack at it. I may still try to work with terminal joiners as I have lots left over after I dissemble the obsolete block system. However, I will likely follow advise and also solder some the track joiners, ie everyother one. One question, though, I am to understand that you have feeders to each section of soldered together track?

Hopefully, I’m on the right track.

David Bourne, P.Eng.

30

Well I have do some more internet reading and You Tubing … to learn that flux and solder are not the same thing … I thought that flux was another name for the liquid solder.

Another question, though, is it seems everyone talks about a 5A current … however, I am looking at Digitrax Zephyr is its output 5A or 2.5A? Voltage output is 12.8V. I am trying to complete my wire requirement calculations.

R = V(wiredrop) / I (boostercurrent)

Thanks,

David

31

David, the Zephyr has a 2.5 amp throughput, but all systems can be boosted, with the individual boosters providing all the way up to 8? amps in Digitrax…someone correct me.

The Super Empire Builder and Chief models come with 5 amp power supplies or I think 8 as well for the Super Chief…again, I haven’t actually learned this. The point is, the Zephyr itself comes to 2.5 amps which is lots for running up to 6-8 locomotives pulling modest loads simultaneously. If you want engines with sound, add about 0.4 amps per engine, and plan power needs accordingly. Make some engines pull heavy loads up grades above 1% and you can add another 0.3 amps per engine.

For wire, if your total powered trackage exceeds 20 linear feet, you would want 18-20 gauge wire feeders up to that point, maybe three pairs spread around to ensure good coverage. Much over 25’, you would want a heavier gauge wire pair bus running along much of the major axis of the track plan, but under the bench. From that bus, you would run 20-22 gauge feeders every 5-6’ or so, and those feeders are best kept under 24" This is where soldering really comes in handy. Wrap the bared feeder ends around the bared bits of bus wire and solder them for solid connectivity. I tried the simple wrap, but got intermittent results soon enough…I soldered all of them eventually.

-Crandell

32

To add to the rail joiner comments, I too learned the hard way. I started my current layout in May of 08. I only had 1 feeder initally on my 8x8 with 2 mains and had no problems running. After reading some posts here I installed 2 more, one to the first main and a second to the inside main. I’ve since added another 9x7 section with a bridge and had another feeder for that section. In the last few months in the original areas I’ve started noticing loco’s stuttering some when running, especially when running slow. Track is totally clean. Problem is the rail joiners. A couple of weeks ago I broke down and spent 14 bucks on 8 gauge bare copper and ran a buss.(You can get smaller wire which would be easier to solder) So far I’ve added about 10 feeders to the buss and things are running smoothe again. The bare buss makes it easier to add feeders over time. Here’s a pic of the buss a joiner soldered to it. As Jeffrey suggested earlier, I also use red for the outside rails and black for inside.

33

Thanks for the picture … any issues with using a bare wire?

Another question, the wires to the Tortoise Switches, where do they go? And what type and size of wire are your using with two conductors as shown?

34

Go out and buy DCC Made Easy by Lionel Strang. THere are diagrams and basic information in there about many of your questions. I did and still go back and refer to it when I hit information overload.[%-)]