These model train control strategies fall into two major catagories, analog and digital. The Arnold rapido analog approach is discussed in the pages of this section. Basically, you control the trains by supplying power to each train selectively. Arnold rapido trains used Direct Current (“D.C.”) for their operation, which allowed for some elegant operating techniques using their track switches, special track sections, diodes and color light signals.
A more modern approach is called command control, and there are a variety of systems in the model train market. For discussion of the Arnold command control sytems and others, please see here.
For further discussion of the rapido coupler and of analog train control, please see the pages listed below: