Looking for cures for two problems right now with Gargrave switches made about 20 years ago which I have.
The gargraves guard rails have a bend at each end intended to collect the wheel flange and move it into the channel between the running rail and the guard rail. I find that in some cases, when the sharp point of the wheel flange hits that bend rather than move over toward the running rail, the wheel goes up and over it and then causes a derailment of the car.
further, the cars and locos with slider shoes can cause derailments in two ways. The slider shoe on the second truck on a car can hit the guard rails and cause derailment, or the slider shoe on a unit which also has a roller pick up for lights on a passenger car or caboose or motor power on a locomotive can be energized and create opening of coil couplerw on the unit. This occurs intermittently depending upon the distance of the roller to the slider shoe and an accidental but unavoidable bridging by the roller as it passes over energized portions of the switch and creates a circuit between the power rail and The guard rail immediately next to the frog of the switch.
I had hoped to avoid Gargraves (or Ross) switches on my current layout, but I find that in some situations they are just too efficient on use of space to eliminate from my design.