DCC - Digital Command Control 
 Introduction   Topics 
Digital Command Control (DCC) is a system which allows multiple model railway locomotives to be operated on the same track at the same time. It allows much greater control over model trains, more operational features and simpler layout wiring. Each locomotive is fitted with a small electronic unit called a mobile decoder which allows it to receive and be controlled by signals sent through the tracks. The base unit which sends out the signals onto the track often has a number of hand-held controllers attached to it, each of which can control one or more locomotives. The LGB 55021 Decoder
Hints on using this MTS (aka DCC) decoder with non-LGB DCC controllers.
Installing DCC on a USA Trains GP30
A detailed guide on installing DCC on this large scale road/switcher locomotive.
Installing DCC on a Proto 2000 GP38-2 Road Switcher in progress
A detailed guide to installing the Digitrax DH163L0 into this decoder so that the numberboard lights work independantly on Function 1.
Installing DCC on a Proto 1000 HO RDC (Rail Diesel Car) model
A detailed guide to installing a DCC decoder into this model locomotive.
Installing DCC on a Kato N RDC (Rail Diesel Car) model
A detailed guide to installing the Digitrax DN122K2 DCC decoder into these model railcars.
 Links   Manufacturers 
JMRI Open Source Java Software for DCC Open Source computer control software Lenz Elektronik GmbH Original designers and a leading supplier of DCC equipment
NMRA US National Model Railroad Association - the standards body for DCC amongst other things Digitrax One of the largest DCC equipment suppliers with a very large range of DCC decoders, particularly strong in specialised plug-in decoders
MyLargeScale.com excellent discussion forum for Large Scale trains; the "Power and Sound" forum is a good place to ask about DCC on large scale. Atlas US model manufacturer with good record of selling models with DCC decoders already installed in N, HO and O scales.