Railway Modelling

- Stud contact
Other systems such as Märklin instead used fine metal studs to replace the central rail, allowing existing three-rail models to use more realistic track.
- Overhead line
Where the model is of an electric locomotive, it may be supplied by overhead lines, like the full-size locomotive. Before Digital Command Control became available, this was one way of controlling two trains separately on the same track. The electric-outline model would be supplied by the overhead wire and the other model (usually steam-outline) would be supplied by one of the running rails. The other running rail would act as a common return.