The Pyongyang Trolleybus Factory (PTBF) is an automotive industry company in North Korea and is the largest trolleybus manufacturer in the DPRK. During its existence, it has also manufactured vans, refrigerated trucks and buses although its main product are the Chollima branded trolleybuses. It has continuously manufactured trolleybuses since 1960, when it built the first trolleybus in the DPRK, a Jinghua BK561 clone.