Command Control (DCC)

Controlling a Model Train

There are two basic ways to control N-Scale model trains.  This actually applies to most model trains, no matter the scale, though there are exceptions (like Märklin HO).  The original and simplest is DC, meaning Direct Current.  The new up-start method is DCC, which means Digital Command Control.

DC

This is the original and traditional method of control.  A basic DC power pack is used, and a direct voltage is applied to the rails, with one rail energized (hot), and the other grounded.  With N-Scale this is usually about a maximum of 12V.   One train at a time can be controlled, and by increasing the voltage through the power pack, the train goes faster.  Some layouts appear to let you run more than one train at a time.  In reality, there are separate independent tracks layed out together, and each one can run one train.

There are newer systems that attempt to get around these limitations by dividing the layout into segments and controlling each segment.   I don’t have any experience with these newer systems at the moment, though I do have a DC power pack or two and run trains on DC as needed.

For many people, DC control is enough.

DCC

This is a newer system that uses an AC voltage with encoded digital information to control multiple trains (and accessories!).  A main command center is used to convert power from a power supply into AC and to control and encode the control info and send it out on the rails.  Each train or accessory has a decoder in it that interprets the data on the rails and if it applies to that train or accessory, it acts upon it.  This includes converting the AC from the track to DC for the motor and applying this DC to make the train go, as well as many other things like turning lights on or off, playing sounds, and many other functions.   It is a standard and many companies make decoders and command stations and other accessories and DCC related items.   I am working to convert my trains to DCC as far as possible.   Some trains come with DCC capability already installed, some are easy to convert (they come with sockets or receptacles for decoders), some are converted by replacing a factory board with a replacement board that includes DCC, and some require work to hardwire a decoder in where one was not foreseen.  This can be relatively easy, or quite hard.

Decoders