Courtesy of Mark Gurries DCC Website
Any discussion about track feeders needs to center on the most common electrical failure point in a track system; the rail joiner. Why? A rail joiner serves two purposes:
1) Mechanical alignment of the rails between independent rail sections (track).The mechanical problems are most obvious and visually observable. Without proper alignment of the rails, our model trains will derail.
2) The passing of electrical current from rail to rail assuming this is a metal rail joiner.
The electrical problems are not so obvious and hidden from view. The electrical connection takes place between the metal of the rail joiner applying pressure to the metal rail. In other words, the invisible “metal to metal” contact area. The common type of metals we use to make rail with all oxidize. This is the metal chemically reacting to the oxygen in the air. Depending on the type of metal, the oxidation or “oxide metal” that results may or may not conduct. Non conducting oxide like that found in brass track prevents the rail joiner from passing current from one rail to the other and at the same time from the rail to the wheel of the locomotive. But even if the oxide conducts, that does not make it a good conductor. Oxide is a highly resistive conduction that is far less conductive than unoxidized or “raw” metal to raw metal conduction can offer.
For locomotives and the top of the rails, we can address this oxidation by cleaning the wheels and track since they are exposed and easily accessible for cleaning. There are many tools and methods to address this problem and we are well aware of problem when we have an engine running poorly on the track. See the CMX Clean Machine.
On the other hand, rail joiners are part of the track infrastructure and are installed once as part of a process of laying track down permanently. In terms of metal to metal contact, we will not have easy access to the metal to get rid of the oxide in the rail joiner/rail connection.
There are two types of modelers.
1) Those that like to solder.
2) Those that do not like to solder.
Those that like to solder will solder both track feeders and rail joiners.