For those not familiar with Digital Command Control for model train sets, this is a simple overview of how it works. It is difficult to ignore the technological trend in our society. Nowadays, even our cars rely on computers as much as mechanics to keep them running well. The same is true in model railroading. An emerging technology called Digital Command Control is taking over the old analog system of operating model trains. These DCC train sets are much more sophisticated and add more realistic magic to the hobby. What is digital command control? Just yesterday I tried to explain it to a muggle in the most simple way I could... it's computers controlling trains.

The Throttle - You are in Control!

The throttle, also called the cab, is the DCC controller interface that a model railroader uses to control the trains, and any other DCC decoders on the layout including motorized turnouts, automated scenery and even layout lighting. These units may either be fixed or walk-around. They typically have buttons to control various functions of the trains, and include a knob or slider to control the speed of the train.

The Command Station - The Dispatcher

The command station takes the signal from the throttle and encodes it into a message that can be transferred along the rails to the trains. The message tells the train exactly what to do or where to go. The most simple systems combine the DCC controller and the command station in the same unit. For all-in-one solutions, some of these units even have a power booster as well. This is the best DCC system setup for an entry level model railroader, or for a small, stand-alone layout.

The Packet - The Message

The packet is the message that gets sent out from the command station to all the decoders on the layout. It consists of a string of data organized into four parts that essentially say, "Hello", "Who", "What", "Bye".... in that order. (Notice there is no "when" because all commands are now!) All the decoders will receive the message, but only the one it is addressed to will respond. The command station sends the message many times to make sure the information is correctly received. New decoders are capable of bi-directional communication, being able to tell the dispatcher "received" as well as where it is on the layout and what it is doing.

The Decoder - The Receiver to Execute the Message

DCC decoders installed in locos (or elsewhere on the layout) have a microprocessor that receives the packet designated for it, interprets the meaning, and executes the command by sending power to the motor, lights, speakers, or any number of layout features. DCC sound decoders and speakers are constantly improving. Now you can upload sounds of your own choosing to the decoder so that the operation sounds realistic, from the horn, to the ringing bell, to the hiss of brakes, the 'clickety clack' or even a conductor shouting 'all aboard!'

To make my point... Two weeks ago I watched an old silent movie. I got bored halfway through and turned it off. I'm glad movie makers have gotten better. Today, so much realism in movie sounds is manufactured... and we believe it because we want to. The same is true with model trains using DCC sound decoders. It's more fun to believe.

The Wrap-up

As a final note, all the components of a digital command control system are pretty straightforward, and can be mastered with a little learning. To keep the hobby alive, train manufacturers are working hard to integrate cool technology, while keeping it as simple as possible. That said, the wiring for DCC doesn't have to be difficult. There are many out of the box DCC train sets available. All you have to do is lay the track, program the loco, and start rolling. So, welcome aboard!