Is/was the a larger than O-scale gauge that used three rail track?

There is a display window in Disney’s California Adventure Park that has some old/school metal rolling stock and two different width three rail track gauges. The smaller one is the standard O-gauge track. The larger one had a couple of O-scale cars on it, that did not actually fit in the track. It rested between the rails. My question is what other scale trains used a three rail track? Did 1-gauge ever use three rail?