 The first batch of 1st generation trains consisted of 126 cars that were originally linked as 21 six-car trains.The cars were manufactured in 1974 under Kawasaki Heavy Industries, Kinki Sharyo, Tokyu Car Corporation (now JTEC), and Nippon Sharyo.As ridership increased on Line 1, the trains were rearranged into eight-car trains in the 1980s.