DCC? newbie here

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Digital Command Control

Conventional model trains run off direct current to the rails. To go faster, you increase the voltage to the rails. To slow down, decrease. To reverse, throw a switch that reverses the polarity of the rails and the train runs the opposite direction. Simple, but if you build a more complex layout with multiple locomotives, multiple trains running - you now have to divide the layout up into blocks so you can run the trains independently of each other, and make sure you throw the right switches so when your train crosses a block boundary, you know you are still in control of it.

Command control is a completely different way of doing things. It provides a constant voltage to the rails. The locomotives have their motors isolated from this voltage (otherwise they'd just run full blast all the time) with a "decoder" or in the old days "receiver" in between. Early command control was very limited and was based on frequency. Sort of like having each cab be a broadcast station, and the loco being a receiver tuned to that station so each loco responded to the cab it was matched with. These systems originated more than 40 years ago, but didn't gain widespread popularity for a number of reasons I won't go into.

In the 1990s digital command control (DCC) came along, utilizing a lot of the same technology that enables your computer to connect to the internet over rather ordinary wire yet perform at extremely high speeds with high reliability.

DCC decoders have an "address" assigned to them, and the cabs send commands to that address. Rather than being on a specific frequency, commands are prefixed with the address of the loco. If a command is sent that says "5901, go forward" only 5901 will pay attention to that command - loco 4230 will ignore it. In the end, much more flexible and reliable.

DCC is common enough and the entry point is cheap enough that it's a good choice for someone starting out - but it's by no means the only option. You can start with plain old DC and go to DCC whenever you are ready. Many manufacturers now offer locomotives that come with DCC decoders already in them - with the capability to run on DC as well. Many more come with sockets or plugs for easy decoder installation... well, those work some of the time - long stories there too.

At any rate, no pressure should be felt to go to DCC right off the bat. The cost of conversion is not great unless you have already accumulated many locomotives. I recommend the NCE PowerCab starter system - street price about $150. Not that much more than a quality DC power pack. I recommend if you do start out cold with DCC, get a loco that is already DCC equipped and I'd recommend Atlas because theirs seem to be the most trouble free. Their "Master" series is DCC out of the box (you do have to set a jumper) and ready to go.

Andy
 
Wow, that definately answered my question. I do understand the "block" system, isnt that about the same in real railroads where signals are placed for each block, (whatever the distance between them) and the signals let the engineer know if the block is clear. Simply put that is.
At any rate, I just wanted to understand what it was because I see DCC in alot of posts, now I know what their talking about. Im still in the very early planning stages right now. So Im not going to concern myself with it now, but your info was noted on my lil yellow stick-it notepad, along with many other notes!! Im going to have to get a bigger notepad!!

Thanks Andy

Zac
 


Andy's post was excellent and comprehensive. If I could just spray it with a little perhaps unnecessary glitter, with cab control and blocks in DC, you have to run the layout. You reach, flick a toggle, and then add voltage. With DC, your engines in any one contiguous section of powered track will all move in the same direction, no matter which way they face.

In DCC, you can tell two different engines to move together so that their front couplers close on each other, and then make them have a tug of war, each trying to move away from the other. Let's see that in DC! Or, if you want to place three different engines snugged up to each other on a short ready track, all in the same "district" (sort of like a block), you can do that. In DC, they'd keep the same distance apart if they're the same model and of high quality....you'd never be able to get them close enough to almost touch couplers to fit on that ready track.

My point is that with DCC you run the trains. Just like in the real world.

-Crandell
 
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My point is that with DCC you run the trains. Just like in the real world.

Yep and you can have a head-on collision too, just like real!

I think it was about 30 minutes before I had my first wreck. At least within 30 minutes after I had installed my second decoder.

DCC is great, I wouldn't go back... but my main point is that if you're just starting out, you don't have to commit to the $$ for DCC right off - it's easy enough to convert, although obviously it's easier before you have 200 locomotives to worry about.

Andy
 
The other nice thing about DCC is if you already have a layout with multiple blocks and cab selectors, converting to DCC goes about like this:

1. Disconnect all DC cabs.
2. Connect DCC track output to Cab A.
3. Set every selector to Cab A.

Yer done... and if you use radio, don't even need to run cab bus wires.

If you don't already have blocks and multiple cabs you can skip step 3!

Reverse loops add a little more complexity, but all DCC systems have fairly straight forward solutions there too. The reversing process is automated and doesn't require a hard toggle switch.

What most people find the most time consuming and trouble-prone aspect of DCC is installing decoders into locomotives and getting everything working the way you want it. I still run into problems even after 10 years at it, but I have the least problems when I do everything myself and don't use any factory wiring. Some brands do plug & play decently (Athearn), pretty good (Atlas), some lousy (Proto). That's why I recommend someone starting out buy a loco that is already DCC equipped.

Another cool thing about DCC is that you can forget all about "lighting modules" and other stuff. Even the most basic locomotive decoder has light function outputs that can be turned on and off with the push of a button on the throttle. Most require some type of resistor in order to use a low voltage bulb or LED, to get maximum brightness without heat buildup - a 12 volt bulb at full blast can get hot enough to melt plastic. Certain decoders such as the TCS A6X have a 1.5v output so you can wire 1.5v bulbs directly to the decoder without frying them. And many decoders have built in effects - strobe, Mars light, Gyralight, ditch lights, dimming... this is all part of the decoder, no extra stuff required. Decoders with these capabilities now cost the same or less than old fashioned light modules alone.

TBQH, until I converted to DCC, I didn't even bother to put headlights in my locos. In order to get one that looked right, I had to stuff all kinds of circuitry under the hood - often of questionable quality. And still, the best you can get is directional lighting. If you run three locos, all three have the lights on unless you put switches on them somewhere. With DCC, I can have full lighting at both ends of every loco, and when I run them in consist I can turn on only the forward facing light of the lead loco.

And of course there's sound. I'm holding out for the next generation of sound capability. Or maybe the 5th generation down the line, dunno. Many people really like it. It does add a new dimension but I'm just not happy with the sound quality and accuracy right now. It also takes up a fair amount of space and in some locos that's already a problem under the hood. Sound tends to sound much better, and be much easier to work with in larger scales (S scale on up) and of course permits much larger speakers that make a world of difference.

The non-DCC sound locos are a compromise IMO, one of the comps being that you have to have the throttle at high noon just to make the sound module power up much less get the loco to move. This makes running a sound and non-sound unit together on DC pretty much impossible; on DCC it's no problem.

Andy
 
The other thing you should know if you are just starting out. Buying anything but DCC would be like buying tapes instead of downloading MP3s. Old dead technology.
 
The other thing you should know if you are just starting out. Buying anything but DCC would be like buying tapes instead of downloading MP3s. Old dead technology.

I still buy CDs. I only download MP3s for stuff that is not available any other way.

I guess it has been a while since I bought a prerecorded cassette tape.

Andy
 
you're both out of date!!!!! bluetooth, wireless music download anywhere any time even from person to person no player required just a bluetooth compatable cell phone =)
 


I still have 8-tracks, and reel to reel!

And vinyl! :D

But I have DCC! :cool:

Rotor

I have vinyl, CD, cassettes, reel to reel - Wollensak and 1950s Webcor mono, Teac 1980s big decks, a Fostex 8-track (not your basic car 8-track).

And DCC. But I also have some 1950s Marn-O-Power throttles too. They have enough guts to run those old DC-71 motors.

I'm just not into having all of my music crammed onto a graham cracker and having to scroll through a cell-phone type interface to find it. Or having all my music vanish one day because I didn't pay my monthly fee. Or having my graham cracker fall down the seat of a taxi.

I also question the quality of many online music sources. I've played with free Napster - the quality is dreadful. It's only useful for checking out a release, as in - to see which version something is, etc.

Andy
 




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