It looks to me like the two left hand rails would move together, and the angled one on the "inside" would act like a guard rail and push the back of the left wheel over, thus pulling right wheel over as well. Some trolley lines had single point switches that worked almost the same way, only it was the point that would force the opposite wheel away from the point of the frog. Maintaining exact gauge was necessary for either type to work properly. I sent these photos to a couple of track experts I know, neither of whom had ever seen such a thing.