A planetary gear train may include: an input shaft an output shaft; first to fourth planetary gear sets including first to twelfth rotation elements; a first shaft fixedly connected to the second rotation element and the input shaft; a second shaft fixedly connected to the ninth and tenth rotation elements, and selectively connectable to the input shaft; a third shaft fixedly connected to the eleventh rotation element and the output shaft; a fourth shaft fixedly connected to the third rotation element; a fifth shaft fixedly connected to the fifth rotation element, the eighth rotation element, and the twelfth rotation element; a sixth shaft fixedly connected to the seventh rotation element; and a plurality of shafts formed by combinations of remaining rotation elements of the first and second planetary gear sets that are not connected to the first to sixth shafts, and selectively and respectively connected to a transmission housing.