I think this is a duplicate Z Needs to be beefed up or discarded.
Command Control systems, both analog and digital, allow you to simulate prototypical train operation on your model railroad. With Digital Command Control you can operate multiple locomotives independently at the same time on the same section of track without a computer and without blocking or other complex wiring schemes. Digital Command Control systems use digital data packets to communicate commands to decoders that control locomotives and turnouts on the railroad.