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What is DCC in Large Scale?

8193 Views 28 Replies 12 Participants Last post by  Mike O
Sometimes when you ask "What is DCC?" you get an answer that is outdated, and really applies to smaller indoor scales.

  1. Gives you control over lights and sounds.
  2. Controls several locos at one time on one track.
  3. Provides constant lighting.

So, What does DCC mean to garden Railroaders?

1. Do we really control of all those lights and sounds? 

Our locos are much bigger, so, for quite a while, we've had more features includeing: smoke, cab lights, marker lights, flickering firelights in the ash pan, mars lights, ditch lights, track lights, fuel tank lights.

 Just how many buttons do we need? How many can we remember?

Fortunately, DCC decoders are really tiny computers, already programed to do all sorts of stuff for us. We just need to select the features we want. That is done by setting up the decoder configuration using CV's (Configuration Variables).

Here are a couple examples:

Our sound decoder plays a crossing signal when we press button "F4" on our hand held remote. If running a modern diesel, we need to turn on the mars lights, and or alternately flash the ditch lights. we can program the motor decoder to do that for us automatically.

We turn on the bell in our sound decoder with F2. That is required when running in a yard doing switching operations. We can also configure the motor decoder to dim the headlight and backup light, which is also required for operation in yard limits, At the same time, we could configure the motor decoder to change the speed range for slower operation with much finer control and reduce the momentum effects so we can stop and start a little quicker. All that with just one button.

The simple truth is, DCC is not so much about instant control as it is about preprgramed control.  Control that is smarter and eaiser, with fewer buttons, yet more realistic.
2. Controls several locos at one time on one track.
Block wiring does that, and so does radio control. So What does DCC do for us.
First, DCC eliminates all wiring except for two wires going to the track. Anyone who has had to deal with buried wires in the garden can appreciate that. We can operate all our turnout, signals, turntables, locos, and the lights and sounds in our  passenger cars and cabooses from the data on those two wires.
Second, It eliminates the glitching and range problems of radio control. A DCC wireless throttle communicates with one or more fixed receivers. Located permanently the receivers provide full coverage. You are never out of range of any loco even one in a steel lined tunnel. You can control any loco, the lights and sounds in any car, or any turnout, signal or stationary device from your remote. You can use any remote to control any train, You can even have two different remotes controlling the same train for buddy operation with a new visitor. Bet of all, there are no frequencies to worry about or batteries to charge.
3. Provides constant lighting.
With the DCC signal on the rails all the time, lighted cars are never a problem. With inexpensive function decoders, you can even control them or configure them to behave automatically or simulate lantern flames or EOT markers. Once again, having an on board computer opens up many opportunities for special effects, Sounds can by automatically activated based on the speed of the train, no matter where the car is. The marker lights on the caboose can change colors based on direction. You can even have the pewee whistle on the caboose blow a warning when backing up or acknowledge the engineers whistle.
Beyond small scale thinking.
LGB makes a working DCC controlled side dump gondola. With so many different manufacturers and decoders to choose from, you can now find decoders that operate servos and do just about anything. Add a decoder to a cattle car with a cattle sound card, any you can let operators know when it is time to pick up the car. If it is full of MOO at the stockyard, or is silent at the packing plant, the cattle car needs to be picked up.
With much heavier locos and more pickup point than the small scales, having 20 or more volts on the rails all but eliminates the oxide problems and stalls at low voltage that analog DC and small scale users experience, In fact, Most DCC LS users are amazed to discover their track is usually so dirty that should they try switching back to DC, their locos just won't run without a lot of cleaning.
DCC with it's industry wide standards for the track signal, wets us do things never attempted or even thought of in the smaller scales.
If you are a Large Scale DCC user, what have you found to be different from your small scale DCC friends?

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Gee, I posted this in January an NOW it pops to the top? :^)
Jerry, I agree.

Many people do not realize they do not need to "CONVERT" to DCC.

Trains with decoders can run on analog DC track.
Switches like yours, or even a full blown block system can still connect some blocks to DC and others to DCC
Analog DC locos can run on MTS and DCC systems like Digitrax (although some systems like NCE do not support an analog loco)

I have run three DCC locos, one Analog DC loco, two battery/RC locos and one live steamer on my mainline loop ALL AT THE SAME TIME.

For the life of me, I don't know why, when you are so concerned about price, you choose to spend over a hundred dollars for sound. The Digitrax SFX064 is under 60 and has more features than the Tsunami.

And, as long as you like to cut cost, how about function decoders? Digitrax TF4's run about $17.00 USD but, Digitrax also makes functionally the same decoder for Kato. I've seen it as low as $5.99.


Did my response to your question on the Digitrax forum help?
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The biggest problem is mounting the solenoid. Most locos have to many things in the way.

One possibility is for Kadee to make the a solenoid in the form factor of the large draft gear box with a short shank standard Kadee on the end and a link from the knuckle to the solenoid. A 18 volt 100 ma solenoid with built in suppression diode would allow most any decoder to operate the coupler.

Wishful dreaming, but I would buy 2 dozen of them.

I have solenoids that work beautifully with the Kadee. All that is required is drilling a small hole in the knuckle for a wire link to the solenoid. There is only room for the solenoid in a couple locos and mounting is a pain. I have one USAT two axle switcher equipped. It is cool, but not worth the effort to do do many other locos. There is no room for the solenoid in the LGB switchers. I might do one Hartland Mac.

As long as you are making predictions, I'll make some.

I would also expect in the not to distant future:
DCC operation will get easier.
DCC systems will throw the next turnout ahead of the loco with a single button. No more fumbling to find the turnout number and keying it in. The same button will also through the turnout behind the last car in your train when you are backing up.

Turning on the loco light with F0 will also turn on lights in all the passenger cars and cabooses connected to that loco. The DCC system will automatically figure out which cars and what caboose is being pulled by you loco. No more keying in car addresses to control the lights. No need to address the cars the same as the loco.

You will not even need to key in the address of a loco to use it. Just put a loco on the track and press "Auto Select" It's address will be displayed. Turn the knob to run the loco. Place another and "auto Select" to run it.
Place three locos on the track WITHOUT pressing "Auto Select" after each one and THEN press "Auto Select" and your throttle will ask "Run Consist? Press "Y" to run all three as a consist or "N" to run only the most recent loco placed on the track.

As you said. in the future...... (if not already)

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Posted By Mike O on 08/31/2008 3:00 PM
Could you not manage the lights in a train through consisting? Might take forever for a long string of passenger cars, but if the car consist was relatively static, you could consist those and then form a consist with the engines and cars as two units.

Unfortunately, Consisting locks together the speed and direction of two or more locos, but, the functions only go to the front loco. (only the front loco should blow the horn, etc.
You can program some motor decoders to respond to the functions sent to the lead loco, but that would be expensive to put motor decoders in the passenger cars and cabooses. Function only decoders don't have decoder assisted consisting capabilities.

I currently use a computer to handle all the lighted cars. It's big advantage is that it automatically figures out which cars each loco is pulling. It is easy to uncouple, some cars, add others or change locos wit no need to do anything to make this feature work. Just press F0 at any time, and the car lights behind THAT loco goes on or off. The nice thing is that they don't switch all at once, instead, the go off one at a time as though the crew was going through the train. Another nice effect is that all the vestibule (porch or steps) lights come on when the loco enters a station, other lights go on and off to simulate passengers unloading or boarding. When the train is ready to leave, the vestibule lights all go off and other lights go on or off when the train is under way. The code to do all this is not very complex. In fact, 90% of the code is to decode and encode throttle/function messages. Most command stations run 386's, already do 90% of the work, and could easily handle the lighting logic.
Posted By Mike O on 08/31/2008 3:00 PM
... snip
The auto recognize function would indeed be a big step forward, and I agree just a matter of time. Once DCC becomes “layout aware” or implements something like Bluetooth, both technically possible today, all you mentioned is possible. I really like the idea of Kadee putting a mechanism in their housing.
... snip

There is no need for bluetooth, or any other new technology. All that is needed is DCC feedback through the rails for car and loco identification.
Digitrax Transponding already does that, and the NMRA proposal for feedback would be another way to do it, if the NMRA would ever come up with a standard that was acceptable.
So, being layout aware is not at all a requirement. There is no need to draw complex track diagrams and fill out huge logic tables to tell a computer how all the blocks, turnouts, and signals are connected.
Think of it like this:
You have one extra wire coming out of the command station. That wire feeds an insulated section of rail in front of all of your stations.
Now, inside the command station is a single small routine that monitors all active decoder addresses. This code could be thought of as a robotic controller for all your active decoders. You could easily program all the robotic behaviors like those little stamp controlled robots they sell at radio shack. DCC command station processors are orders of magnitude faster and more powerful. Compared to the complex programs those little robots do, the code to do all of the above is simple. For example, a decoder enters a station track, the robotic code needs to know if it is a loco or a car. Simple, if the decoders DCC speed is set to 0 It MUST be a car. ( something else like a loco had to move the car into the station siding. ) So, one simple IF statement can handle something that would be quite complex in the toy robot world. To do most of the above, the code would, if the address was a car, consist it to the last loco to enter the station. If the address is a loco, remember it's address and add cars to it. Finally, when a function is sent to a loco, also send the function to each non loco address in the consist. In JAVA PEARL or PYTHON that is about 5 lines of code. Probably less than 50 bytes of code in most command stations or hand held DCC throttles.

Posted By Mike O on 08/31/2008 3:00 PM
... snip
I found a thread posted way back in 2003 where you posted about automatic couplers http://archive.mylargescale.com/forum/topic.asp?ARCHIVE=true&TOPIC_ID=17692 . Unfortunately the links are not valid anymore and Google didn’t find them. Any idea if they are still around?

Sorry, Mike, both my web sites got blown away, I think I have a backup on an old computer in the garage, but I haven't been motivated to restore it. I'll keep it on my list of things I need to do.
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