Tag, Apparently they evolved over time more than I realized. Mine is only a few years old, and it is not an oscillator. The cylinder is rigid and the piston has a spherical shaped head. I'm having a senior moment and cannot recall the name of the rig, but there is a little white nylon(?) tab sticking up. that must be held down while rotating the wheels forward or reverse to set the direction. When I think of oscillators, I see in my mind's eye the Mamod types where the cylinder actually does move in an arc motion. Keep your steam up! Walt & Mr. Lunkenheimer
