# newbie on dc and dcc



## ExONRcarman (Feb 7, 2017)

ok so ive read a lot on this forum about dcc compatibility and even how to do it. But i could not find an actual " definition " as to what dcc is. So if one of you guys would like to school me on this it would be greatly appreciated. Thanks


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## MtRR75 (Nov 27, 2013)

Digital Command Control

https://en.wikipedia.org/wiki/Digital_Command_Control


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## traction fan (Oct 5, 2014)

*DCC*



ExONRcarman said:


> ok so ive read a lot on this forum about dcc compatibility and even how to do it. But i could not find an actual " definition " as to what dcc is. So if one of you guys would like to school me on this it would be greatly appreciated. Thanks


ExOncarman;

D.C.C. stands for Digital Command Control. It is a system somewhat similar to the radio control used in model airplanes, and cars. The difference is that the signals that control the locomotive are sent through the rails, instead of through the air. Using DCC you can control more than one train on the same track. DCC also has sound available as an option. This lets you blow the whistle, ring the bell, and hear the sound of the locomotive working. The system is very popular, and is gradually reducing, but not totally replacing traditional DC (Direct Current) control. DCC wiring is much simpler than the older DC system. In its basic form, you connect two wires from the control unit to the track. That's it! Your layout is now wired. DCC uses a decoder circuit board inside each locomotive. Different digital commands go out on the rails, and are received by the appropriate loco automatically. Many new locomotives come with DCC decoders already installed. Older, (DC) locomotives can be converted to DCC by installing a decoder. There is a wide choice of decoders available. DCC costs a bit more ($25-$100) more depending on the loco, and whether you want sound or not. A basic control system costs about $175-$200. 
In my opinion, and that of many other modelers, DCC is well worth the extra cost. Also there would be some offset of original expense because you won't have to buy a bunch of toggle switches and wire, to build a control panel. DCC can also be used to control turnouts (track switches) and any other accessories you wish, by adding decoders to those items. It also makes wiring reverse loops easy, and lets them operate automatically using a reverser circuit board. If you want more info on DCC, there are several books available. 

Hope that helps you;

Traction Fan:smilie_daumenpos:


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## DonR (Oct 18, 2012)

Mtrr and Traction fan are good teachers...very
useful information.

But, as usual, I would like to call the class to order
for some additional DCC studies.

You can do so much more with your trains on a
DCC layout without a lot of switch flipping and
commotion.

On a DC layout, ALL trains on the track will move
when you raise the power pack speed control. You
have no individual control. But on a DCC track
you could have 5 or 6 trains on the track but just a push of
a button and the one you select
obeys your commands. The others stay still. You can get one going, then push another button and bring a 2nd one along behind it. Or...you can get one going clockwise on your
layout while the other goes counter clockwise on
the same track. (you need passing sidings to
prevent collisions).

And while the 'innards' of DCC are high tech, the
human interface is utter simplicity. If you can
use a TV remote you can run a DCC layout right
out of the box.

Oh yes, one other thing, your loco headlight and
the lights in passenger cars stay bright regardless
of the train speed, they don't dim when you slow
and they don't go out when you stop.

Don


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## mesenteria (Oct 29, 2015)

To continue, in order to prevent that problem, the one where all trains on the tracks that are being powered moving in concert, in the same direction at the same time, those in DC have used a block system that breaks the power segments into defined lengths. That way, you can keep one locomotive still while another moves simply be ensuring the immobile locomotive is on rails that are NOT getting any power. This makes it complicated, but still...that's how thousands got their layouts to run realistically.

With DCC, the decoder resident in each locomotive receives instructions, digital ones, that tell it how to meter (an important word there) voltage to the DC motor. Yes, all motors are DC...period. At least in HO they are for NMRA-compliant train systems. Europe's Marklin trains (German) have dots in the center of each tie that make it an AC current system, but I digress...

So, in DCC, the rails get a constant digitally controlled AC current. It's always near 15 volts in HO. Why doesn't the locomotive take off like a scared rabbit? Because the decoder has received no inputs to meter any voltage...at all...to the motor. When you do that through the throttle, the locomotive moves. It's that simple.

So, while in DC every locomotive must move when the rails under them get voltage, you can have two DCC locomotives on those same rails and neither will move...or one will if you direct it to. In fact, one thing that is absolutely impossible in DC is to have two locomotives move toward each other and lock couplers...UNLESS...their couplers lock over a gap in the rails (meaning each loco is running on its own block). In DCC, because the decoder tells the motor which way to rotate with its metered DC current, the locomotive will reverse or move forward, even toward each other.

I hope that helps.


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## MtRR75 (Nov 27, 2013)

DonR said:


> On a DC layout, ALL trains on the track will move when you raise the power pack speed control. You
> have no individual control.


True, UNLESS (as Don knows) you divide your layout up into blocks using insulated rail joiners, then wire electrical switches to each block. The you can control 2 DC trains independently. This is the way that most layouts were done until DCC arrived about 20 years ago. And some modelers still prefer DC layouts. But it does take two transformers and a LOT more wiring. And designing a DC layout to run more than 2 trains independently get REALLY complicated.


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## Cycleops (Dec 6, 2014)

So now you know which will it be?


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## ExONRcarman (Feb 7, 2017)

Wow. awesome. ok. lots to take in. But i definitly like the sound of dcc. and considering my entire collection is in storage for an upcoming move, rebuilding a dcc will be simplicity itself


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## ExONRcarman (Feb 7, 2017)

Thanks a ton guys


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## CTValleyRR (Jul 26, 2014)

DonR said:


> And while the 'innards' of DCC are high tech, the
> human interface is utter simplicity. If you can
> use a TV remote you can run a DCC layout right
> out of the box.
> ...


You know that's not a given, right? My father in law, after we had unpacked and set upmhis new TV, spent 30 minutes screwing things up with the remote and complaining about how everthing is so complicated these days...


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## DonR (Oct 18, 2012)

CTvalley

I hasten to agree...there are so many menus and 
controls on today's TVs that confound many of us.

I don't even try to use some features on mine...
but then, I'm the one who still has a 60s Western 
Electric rotary dial phone that is still on line

Don.


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## Cycleops (Dec 6, 2014)

ExONRcarman said:


> Wow. awesome. ok. lots to take in. But i definitly like the sound of dcc. and considering my entire collection is in storage for an upcoming move, rebuilding a dcc will be simplicity itself


I shouldn't count on that, depends how old your collection is. If they don't have a DCC plug you'll have to hard wire but that's not too difficult, just time consuming. Just do them in bite size stages. It might be wise to do a stall test on them to check how many amps they are drawing. Any probs just ask on here.


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## flyboy2610 (Jan 20, 2010)

It has been said that DC controls the track, while DCC controls the locomotive.


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## ausmodeler (Sep 24, 2017)

This is not a reply but an additional question from a real newbie just starting out on an HO system and plannng on using DCC. I am a little confused on the electrical: with DCC is there simply one connection to each side of the track and do you not have to create a bus wire around the system with feeders to all the tracks sections when using DCC?


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## MtRR75 (Nov 27, 2013)

ausmodeler said:


> This is not a reply but an additional question from a real newbie just starting out on an HO system and plannng on using DCC. I am a little confused on the electrical: with DCC is there simply one connection to each side of the track and do you not have to create a bus wire around the system with feeders to all the tracks sections when using DCC?


Theoretically, you only need one pair of wires -- IF your layout is small and all of your rail joiners are soldered. In practice, you should solder your rails in about 3-6 ft sections with tiny gaps and unsoldered joiners between the sections. This allows for expansion and contraction of the base material under your rails. Then you run a pair of bus wires from your power source to the track, with a pair of feeder wires attached to each section.

Also, I never solder turnouts to their adjacent rails. This makes it easier to change out a turnout if it fails. You can attach pairs of feeder wires to the turnouts if you notice a power drops across them. But so far I have not needed to do this.


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## ausmodeler (Sep 24, 2017)

Is the power source for the buzz wire, the DCC power source or a separate power source ? that?s been my confusion. I understand how to run Busse wires all the way around the set up and run feeders to multiple sections of the track but I?m unclear as to where the power source for those bus lines comes from. Thanks for your input so far


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## CTValleyRR (Jul 26, 2014)

ausmodeler said:


> Is the power source for the buzz wire, the DCC power source or a separate power source ? that?s been my confusion. I understand how to run Busse wires all the way around the set up and run feeders to multiple sections of the track but I?m unclear as to where the power source for those bus lines comes from. Thanks for your input so far


You say "buzz wire", "Busse wires" and "bus" all in the same post. Is it safe to assume either fat fingers or creative autocorrect, and that you are always referring to your bus wires?

One end of your bus will connect to your DCC booster / control unit / whatever. The other will connect to something. As others have said, at it's simplest, the other just connects to the track. One wire to each rail. As long as you don't have a reversing section, that will work fine. You don't actually need to solder the joiners. Extra feeders and soldered joints is just extra insurance against having power dropouts.

Let's say you want that insurance. You can connect those output / bus wires to a pair of terminal strips under the layout and take feeds off of those.

You can also run your bus under the layout and connect feeders to those wires. It ISN'T a loop, though. Run the busses straight under the layout, and terminate them when you've covered enough space.


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## DonR (Oct 18, 2012)

As usual, our members have done a good job 
answering your question.

But, poor ole Don likes to come in when there
is a newbie on DCC with some additional
information.

A DCC (Digital Command Control) system is comprised
of a Controller, it's power supply, and a decoder in
each locomotive, each with it's own 'address'. 

The Controller is connected to the track with 2 wires,
one to each rail. They carry the always live 14 or so modified AC voltage. Large layouts operate better with a track 
connection every 6 feet or so to assure a continuous
dependable electrical feed.

You push buttons and turn a speed control and the
controller sends those commands digitally through the
track to the
loco (or locos) you have selected. You can have
3, 4 or more locos operating at the same time, each
individually controlled.

Don


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## sachsr1 (Mar 3, 2016)

ausmodeler said:


> Is the power source for the buzz wire, the DCC power source or a separate power source ? that?s been my confusion. I understand how to run Busse wires all the way around the set up and run feeders to multiple sections of the track but I?m unclear as to where the power source for those bus lines comes from. Thanks for your input so far



Most DCC systems are off the shelf commercial units, and they are pretty straight forward. My NCE system has a power output that can be one wire straight to the track or run a longer bus wire with feeder wires. They basically hook up the same way as DC controllers. 
I think of DCC like I think of a smart phone. On a landline you have input all the digits of a phone number to make it dial. On a smart phone you tap the picture or name of the contact, and the software dials the number. I don't really care or understand what's going on under the hood, but the phone is doing what I want. They are both phones, but they function differently.


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