DCC or Digital Command Control sends signals to the locomotives through the rails. Multiple locomotives are independently controlled within the same block.  Train operation depends on the decoder installed in each block. Programming is done to allow users to set the decoders address.

A programming track can be implemented in two ways. Program the track onto your workbench or build it into your layout. The former approach allows simple control and testing facilities. The latter approach incorporates the track into the layout and is easily moveable. It also allows programming a dead zone for track protection. For more information on dcc programming and other model railroading tips and ideas get the Model Train Techniques ebook available free with your first months membership to my online model train club.