Couple of things here. 346s derailment on Kenosha pass had nothing to do with blind drivers. That was from excessive speed.(runaway) Any loco blind driver or not hitting a sharp curve like that at 20+mph would likely roll.
Drgw called for the blind tires to be wider. This allows for them to stay on the rail over sharp curves or sections with gauge issues. I never really understood why or where this thought of blind driver causing more derailments. I do understand that if(like in the case of RGS 40) you drop the #4 driver, #3 and #2 will likely follow. This could cause more damaging and dangerous derailments than if all the drivers were flanged.
Also I can say for a fact that a c-19 will negotiate a 35° curve without the need for extra rails to keep the blind drivers from dropping off the rail. To be fair Knott's did in fact have 1 extra rail on the gauge side of the outside rail to hold up the blind drivers. But not on all the curves that sharp. Management gave me a funny look when I asked what good will that do to hold the blind drivers up on the otherside of the curve.
Jeff Taylor
CRRM curator of equipment and rolling stock.