Three feet was the gauge chosen by American railway engineers faced with the task of bringing full sized trains into difficult mountainous terrain. Despite the narrow gauge, the locomotives and rolling stock are definitely not small. This fact, combined with the exciting scenic possiblities offered by mountain-top locations, has helped to make HOn3 increasingly popular with modellers all over the world.

The wiring of these new turnouts is a development of both the Insulfrog and Electrfrog designs. The stock-rails are wired to the centre-rails at the factory, which in turn are connected to the corresponding frog-rail. This means the turnout is completely live(except for the tip of the frog) with no extra wiring required. If the turnout is being used as a switch to isolate a section of track then it is simple job to remove the wire that joins the centre-rail and stock-rail and it will work like a current Insulfrog.