A planetary gear train of an automatic transmission for vehicles may include an input shaft adapted to receive torque of an engine, an output gear adapted to output changed torque, a first planetary gear set having a first sun gear, a first planet carrier, and a first ring gear as rotation elements, a second planetary gear set having a second sun gear, a second planet carrier, and a second ring gear as rotation elements, a third planetary gear set having a third sun gear, a third planet carrier, and a third ring gear as rotation elements, seven rotation shafts connected or selectively connected to one or more rotation elements, other rotation shafts, or a transmission housing, and six friction members interposed selectively at connecting portions of the rotation shafts.