KTX (Korea Train eXpress) is the first high-speed train operated in Korea and its highest speed reaches 300 km/h. Korean high-speed trains are mostly operated on the railroads exclusively designed for high-speed trains, but the sections of Seoul~Gwangmyeong, nearby of Daejeon station and Dongdaegu are operated on the existing tracks having the speed less than 150 km/h. With this paper, we’d like to analyze the lateral force that occurs between the wheels and the rail when high-speed trains were operated on the existing track section to suggest an appropriate driving speed for high-speed trains. As the rigid wheel base of the high-speed train is 3m which is about 50% longer than normal vehicles, it works as an advantage for high-speed driving. However, as the lateral force becomes higher than normal vehicles when driving on curves, plans to reduce wear-outs on the wheels are required.
