Changchun Railway Vehicles
When operations on the Metro started in the 1970s, newly built DK4 passenger cars were used, made for North Korea by the Chinese firm Changchun Railway Vehicles. A prototype train of DK4 cars was constructed in 1971 and the first 15 cars were sent to Pyongyang on July 30, 1973. 112 cars had been provided to North Korea by September 1978, but eventually 345 cars were acquired.