The Pacific Class 5 was a high-speed steam locomotive developed to haul express passengertrains on major routes such as the Busan-Seoul-Sinuiju Line.It was the fastest steam locomotive in Korea, capable of 110 km/h, and was engineeredto suit both the properties of Korean coal and the operating conditions of the nation'srailways, which are characterized by steep gradients and numerous curves.Produced from 1939 until just before Korea's liberation (1945), the type served on passengertrains until 1967, when diesel locomotives became widespread.