How is DCC different to DC?

DCC Controllers, or Command Stations, are the DCC equivalent to the DC power supply. However rather than simply provide a variable voltage to the tracks like with DC, DCC controllers provide permanent power to the tracks, and include data on the power supply, so that DCC Decoders – fitted into locomotives, or installed on the layout itself – can be sent information as well as power.

These DCC decoders each have an address assigned to them (chosen by the user), so the DCC controller can send a command to one decoder, and a different command to another decoder, even though the decoders might be on the same section of track.

Consider the following example: let’s say you have 2 locomotives, sitting on the same section of track. With a DC throttle and locomotives, as the speed control is advanced, both locomotives would respond to the DC throttle (because they are on the same section of track). However with DCC, the throttle would be sending the information to 1 of the locomotives only, so that locomotive would change it’s speed, while the other locomotive would ignore the throttle changes.

This allows more flexibility in the control of locomotives than DC, and while DCC layouts are often broken into separate sections, it is not mandatory, and it is possible to operate an entire layout on a single section of DCC.