DCC information

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What Is DCC?

Digital Command Control allows you to operate several  locomotives independent of each other at the same time with varying speeds and directions on the same electrically controlled section of track.

How Is DCC Different from DC?

Multiple Train Control Using Digital Command Control

With DCC, train operation depends on the decoder installed in the locomotive. The track is powered by a command station and/or booster connected to a transformer. Each locomotive operates independently over the track. Several locomotives can be moving at different speeds and in either direction at any time on the same electrical section of track. Blocking is not required for train control. It's easy to move engines around in the yards and park them close to one another without worrying about where the insulated sections are. It's easier to operate trains in the wide open spaces, too! DCC lets you run your trains instead of running your track.

Digital Command Control will revolutionize the way you run your railroad and it doesn't have to cost an arm and a leg. Whether you have an existing railroad or are starting a new one, DCC can work for you and let you run your trains the way you've always wanted!

Why DCC Is Better?

  • Simpler wiring.
  • Control 9999 engines with only 2 wires.
  • DCC voltage always present on the track to feed lights, functions, accessories.
  • Turnouts/signals can be controlled with the track.

DCC Advantages

Operation is far more exciting with each train running independently. You can create more lash-ups (consists, MUs) and match the speeds of locomotives from different manufacturers. You can program realistic acceleration and deceleration rates, or limit the top speed of a locomotive.

DCC has advantages for everyone from the beginner to the advanced modeler and for every layout from the smallest to the largest. For beginning and intermediate modelers (most modelers classify themselves at this skill level) the advantages of reasonably priced simple command stations and simple layout wiring are very important. Start with a relatively low cost command station and add components as your interest grows. If you decide you want more advanced features and functions from your command station or if you want to add a computer, it's an easy transition from basic to full-featured command stations. The equipment you already own moves on with you as you add more features to your system. Your largest investment in time and money is in the decoders you install in the locos. These are upwardly compatible as you expand and add to your system. By simply adding components you can grow into a more advanced system at your own pace and as your budget allows.

Most home layouts are small or medium sized. They typically have a limited amount track available for block control. DCC has a real advantage in these situations. Since blocking is not required you can operate more locos in a smaller area.

For the large home or club layout DCC offers truly prototypical operation and minimum wiring hassle.

Modular layouts running with DCC can operate more than 2 or 3 trains at a time. Let's face it, the outside loop running clockwise and the inside loop running counterclockwise all day isn't very exciting. The ease of wiring makes modular hook up simple and lets you get operating sessions up and running more quickly.

DCC Limitations

The only big limitation is the one-way communication from system to decoder. Lenz (Railcom) and Digitrax (Transponding) have developed solutions for two-way communications that are inexpensive and compatible with existing products.

Future of DCC

  • Two way communication
  • One decoder in every engine and car
  • Car/engine "finder" - where is the car on the layout?
  • Automatic train routing and advanced signal system
  • Smaller and smoother decoders
  • Car detection accessories for yard database

Basic Principles - How Does It Work?


With Digital Command Control (DCC) you use a handheld throttle to send information to a command station telling it what you want train X to do. The command station then takes this information, transforms it into a stream of digital packets and sends it to the booster. The booster will add power to the packets, and broadcast the combined signal to the rails.

  • DCC system sends commands
  • Loco decoders receive and act


The decoder-equipped locomotives on the railroad constantly listen to the 'packet' broadcast. Each information packet has an address component to it which should match the address of one of the decoders.

The decoder which is not the intended recipient of the packet simply ignores the data and its locomotive keeps on doing whatever it is doing - running forward, backward, lights on etc.

The decoder, to which the data packet IS addressed, will translate the packet into command for the locomotive such as 'slow down', 'stop', 'reverse direction', and the locomotive will behave accordingly.

• The power on the tracks is alternating current (AC), and not DC or direct current.

• Full power is running through the tracks at all times while the system is turned on. Voltage is sent by pulses to a decoder in a locomotive which controls the locomotive's speed.

• The polarity of electricity on the rail does not control locomotive direction. The decoder in each locomotive converts AC current to DC and controls the voltage and polarity that travel through the electric motor. When the decoder receives the digital signal sent from the command station, the decoder applies the appropriate amount of voltage and polarity to the motor based on the speed and direction in which you want the locomotive to travel.