South Korea’s KTX high-speed service began in 2004 with KTX-I trains.
KTX-I is South Korea’s first-generation high-speed train, based largely on France’s TGV Réseau technology. Hyundai Rotem assembled the trains in South Korea, while the initial technology transfer involved Alstom. Each trainset consists of power cars and passenger cars designed for high-speed operation on the Seoul–Busan route.
The KTX service opened on April 1, 2004, linking Seoul with destinations including Busan and Mokpo. Before the full high-speed network was completed, trains used both new dedicated high-speed tracks and upgraded conventional railway sections.
KTX-I is sometimes confused with KTX-Sancheon, a later South Korean train design introduced in 2010. The KTX-I name identifies the original train type, not the railway itself or every KTX-branded service.