DALIAN, July 25 (Xinhua) -- Dalian, one of the largest cities in northeast China's Liaoning Province, started the construction of its first metro system project Saturday.

    The project includes Subway Lines 1, 2 and 4. With an estimated overall investment of 22 billion yuan (3.2 billion U.S. dollars), the three lines are designed to extend 58.1 kilometers and carry 38, 000 passengers per hour at the speed of 80 kilometers per hour.

    Subway Lines 1 and 2 are expected to be completed by the end of 2012.

    Timetable for the construction of Line 4 is not yet revealed.

    With the approval of the National Development and Reform Commission, Dalian will build nine lines for the metro system, which extend 262.9 kilometers. But a detailed plan is yet to be published.