The railroad industry has existed for about 200 hundred years. German toy maker Marklin circa 1890 began manufacturing model trains that used a wound spring clockwork mechanism to propel the locomotives. With the advent of electricity, electric motors were eventually miniaturized to sizes that world fit into model trains of varying scales.
In the early direct current (DC) or analog systems, current was supplied to the locomotives through the track. As layouts began to grow, controlling smaller sections on track independently through the use of insulated rail joiners became necessary. Individual sections of track, turnouts, and other layout accessories were controlled through large panels of toggle switches. This in turn produced much more complex wiring schemes and drove up power consumption and cost. The expansion of the hobby and the growth in the number of manufacturers created the need for scale standards so hobbyists could mix and match products from the different manufacturers. DC systems were still limited in the number of locomotives that could run simultaneously and the direction they could travel etc.
In the late 1900s, again in Germany, a company under contract to manufacturers Marklin and Arnold began developing an advanced digital command control system. When the National Model Railroad Association (NMRA) eventually settled on a digital standard, much of the Marklin system was included. The standard was first published in October of 1993.
How DCC systems basically work:
A DCC system consists of one or more power supplies, command stations, decoders, and many use remote throttles. With a DCC system there is no need to segregate the track into smaller sections for power management. The system supplies an even voltage to the entire layout at all times. Each locomotive has a DCC decoder installed, which receives power and digital signals from the track and routes power to the motor as required. The decoder for each locomotive is configured with an individual address and will not respond to messages sent to another decoder (much like an email addressed to one person will not be received by another). This allows each locomotive to be controlled independently. Power can also be used to activate functions such as lights, sound generators, and smoke generators for steam engines. Other decoders called stationary decoders can be used to manage other features of the layout including turnouts, uncouplers, crossing signals, lights for the railway or street lights, or lights inside buildings, station announcements, and many others.
While the DCC systems can initially be costly with the command station, larger power supplies, and decoders or more expensive locomotives with the decoders pre-installed. In the long run they are more cost effective as the maintenance cost is greatly reduced and the system can be easily upgraded and expanded. The DCC standard makes the manufacturers components interchangeable which can also save on cost. There are other cost savings to consider. The required wiring even for larger layouts is simpler therefore less costly, as well as a reduction in power consumption. You will also get more consistent and reliable power to your entire layout.
Better control for more realism is the significant benefit of the digital command control system. This is mainly achieved through what is called “speed steps”. Speed steps can be thought of as how many notches there are between idle and full throttle. DCC systems can have 14, 28, or 128 speed steps. The more speed steps your throttle has, the more granular control you have over the speed of a locomotive. Twenty-eight speed steps are now the standard for today’s systems. With a 128-speed steps throttle you can make a locomotive smoothly crawl at a very slow pace. So DCC gives you the power to control and maintain realistic locomotive speed. This is a great advantage for railyard operations.
So; with much greater control for more realism, much less complex wiring requirements, and greater flexibility in upgrading and/or expanding any layout, DCC systems have greatly changed the way model railroads are operated for the better.