Planetary gear train of automatic transmission for vehicle

A planetary gear train of an automatic transmission for a vehicle comprising:

• an input shaft receiving torque of an engine;
• an output shaft outputting torque of the engine;
• a first planetary gear set including a first rotation element, a second rotation element, and a third rotation element;
• a second planetary gear set including a fourth rotation element, a fifth rotation element, and a sixth rotation element;
• a third planetary gear set including a seventh rotation element, an eighth rotation element, and a ninth rotation element;
• a fourth planetary gear set including a tenth rotation element, an eleventh rotation element, and a twelfth rotation element;
• a first shaft connecting the first rotation element to the fifth rotation element and the ninth rotation element;
• a second shaft connected to the second rotation element and directly connected to the input shaft;
• a third shaft connecting the third rotation element to the seventh rotation element;
• a fourth shaft connected to the fourth rotation element;
• a fifth shaft connected to the sixth rotation element and selectively connectable to the third shaft;
• a sixth shaft connecting the eighth rotation element to the twelfth rotation element and selectively connectable to the third shaft;
• a seventh shaft connected to the tenth rotation element and selectively connectable to the fourth shaft;
• and
• an eighth shaft connected to the eleventh rotation element, selectively connectable to the third shaft, and directly connected to the output shaft.