That's what's kinda cool about the Marx "dots" & strips. They fit in tight spots.
You don't need to have the "real" ones. Electric tape and a folded copper scrap with presoldered wire works well. (the tape goes between dot & rail to insulate. Once you have the right spot or strip length you can better mod any track with a well planned cut and pull them right off. (clean any goo)
Some wheels just plain don't like tripping the antiderail. Maybe a swap?