Wire Gauge Standards for Model Train Layouts Wire Gauge Standards for Model Train Layouts. The insulation on the outside of the wire also varies greatly. In most cases, because we are dealing with relatively low voltage and amperage and in normally stable temperature and humidity climates, our wiring does not require any extra insulation. Wiring a Model Railroad Track | MRA Wiring a Model Railroad Track. Wiring a model railroad track is an essential part of any model railroad layout. Find out how important and helpful it can be to keep your wiring neat early on when wiring model railroad tracks. When you go under your layout after everything is complete, and you’re trying to troubleshoot an electrical problem,..