The first prototype unit (NY1) (neiran yeli chuandong meaning diesel-hydraulic transmission)[REF] was produced in 1959 at Sifang locomotive works, and given the name 'Weixing'.
Locomotive design was similar to German diesel-hydraulic machines such as the DB Class V 200 - the machine had a pair of high-speed diesel engines, each driving a separate hydraulic torque converter based transmission resulting in low mass compared to contemporary diesel-electric machines.