From their site,
How do I create isolated rails for non-derailing?
On the track leading to the frog end of the switch (the end of the switch with the diverging track (V shape end)) make a cut on the outside track rail 4 or 5 inches from the end of the switch. This creates an isolated rail. See this drawing for which rail to cut. Be sure to remove any metal particles from around the cut to avoid a possible connection between the rails. Install a jumper on each isolated rail long enough to connect them to the switch machine terminals per wiring diagram.
Why gargraves and not Ross?
Ross are said to be a little more reliable?
None of the "scale" switches are non-derailing stock as far as I know. I know that Ross, Gargraves, or Atlas are not. I believe MTH ScaleTrax actually breaks the mold and has non-derailing features native.
Does your switch have a non-derailing option?
A non-derail option is a function of the switch machine and not the switch itself. Our switches can be operated with many different motors, some of which have the non-derail capability and some that do not. That said, the RossReady switch with motor attached does indeed have that easy to wire option. (dz1000 switch machine instructions)
BTW, I have made some prewar American Flyer O gauge switches non-derailing. They work pretty well. My motivation for doing these switches is that they mate up with AF O-40 track. I bought 15 of them for about $25 at a train show a few months ago.
GarGraves switches are not wired through for continuous power through the center rail. The user will need to provide track power to each end of the switch (three places). This can be done by adding jumper wires to the center rails of the track leading into the switch. A drawing of this is available on the diagrams and instructions page of the website.