Planetary gear train of automatic transmission for vehicle

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

• an input shaft for receiving an engine torque;
• an output shaft for outputting a shifted torque;
• a first planetary gear set having first, second, and third rotational elements;
• a second planetary gear set having fourth, fifth, and sixth rotational elements;
• a third planetary gear set having seventh, eighth, and ninth rotational elements;
• a fourth planetary gear set having tenth, eleventh, and twelfth rotational elements;
• a first shaft fixedly connected with the second rotational element and the twelfth rotational element, and selectively connected with the input shaft;
• a second shaft fixedly connected with the sixth rotational element, and selectively connected with the input shaft;
• a third shaft fixedly connected with the eighth rotational element, and fixedly connected with the output shaft;
• a fourth shaft fixedly connected with the first rotational element, the fourth rotational element, and the tenth rotational element;
• a fifth shaft fixedly connected with the third rotational element, the fifth rotational element, and the ninth rotational element;
• and
• at least one additional shaft each selectively connecting a corresponding element to the transmission housing, the corresponding element being a rotational element of the third and fourth planetary gear sets that is not fixedly interconnected.