The SRT trains are an excellent choice for anyone traveling long distances across South Korea, offering a modern and efficient experience. Departing from Suseo Station in Gangnam, these high-speed trains are especially popular for journeys between major cities like Seoul and Busan. Passengers can choose from different travel classes, including the spacious 1st class and the comfortable 2nd class. All SRT trains are fully air-conditioned, with reclining seats, power outlets, and ample space for luggage. Onboard vending machines and snack trolleys provide light refreshments, and professional staff ensure a smooth journey with many able to assist in English. Busan Station is one of the largest transport hubs in South Korea — as the terminus of the Gyeongbu Line, it is served by KTX high-speed trains as well as regular Mugunghwa train services and enjoys a central location with easy access to the city's main attractions. KTX departs from Busan Station (Jungang-daero, Dong-gu, Busan) and arrives at Seoul Station (405 Hangang-daero, Yongsan-gu, Seoul) — a distance of 423.8 kilometers with over 50 daily KTX departures from Busan to Seoul and over 70 from Seoul to Busan.

Korail operates several types of high-speed rolling stock on the Seoul and Busan corridor. The KTX Sancheon trains are the most widely used — a domestically built second-generation bullet train that is faster, quieter, and more comfortable than earlier models, with generous legroom, wide reclining seats, and power outlets at every seat. The older KTX Cheongryong trains still run on some departures and remain a reliable option at the same maximum speed. For travelers departing from Suseo Station, the SRT service provides a popular direct train alternative running on the same high-speed rail infrastructure. ITX services also operate on the route at lower speeds with more intermediate stops — ITX-Saemaul fares range from $24 to $33, making ITX a popular budget-friendly option. Mugunghwa trains offer the lowest fares at $17 to $26, though Mugunghwa trains take up to 5.5 hours for the same route.

The KTX is the most convenient transportation mode for traveling between Seoul and Busan — trains provide more legroom and allow passengers to walk around, connect directly to subway systems at key stations, and arrive directly in the city center. KTX trains operate at a maximum speed of 305 km/h, covering 423.8 km in as little as 2 hours 15 minutes, making the KTX faster and more reliable than buses or driving. KTX trains offer Economy Class and First Class seats: Economy Class is comfortable with reclining seats and good legroom, while First Class seats offer wider seating and extra comfortable amenities. KTX ticket prices range from $43 to $70 depending on class and travel date; discounts of up to 30% apply for frequent travelers on KTX. Tickets for KTX Sancheon and KTX Cheongryong services can be purchased online, from ticket desks, or from self-service vending machines at the station — book KTX tickets online up to one year in advance; purchase tickets at stations only up to one month ahead; during peak times such as weekends and summer, book at least one month ahead. E-tickets can be used directly without physical redemption.