A company called Tru-Scale used to produce turnouts where the frog closed to make a smooth ride. This was in the 50s and 60s and some of them show up in used bins today (I have one in my junk drawer). They were made with a single unit for the points, closure rails and the attached bit of the frog so that when the points moved the frog rails shifted over to close the gap.
There is a bit of discussion about trap and catch points -- structurally the same thing, but one derails trains going the wrong way on a line while the other derails trains going the right way but to the wrong place.
Called a derail in N.America. Can be a single point, a pair of points, pair of points with a frog (a switch) or a casting that picks up the wheel and drops it outside the rail. Usually there is a rail to keep the wheels from going too far to the side.